V8 300GT to 300xs

[Mastercraft241]

Im swamping out my V8 300GT for a 300xs. I was wondering what kind of performance changes i should be expecting if any at all.
I'm getting around 66 with my 300 with a 31" set back. What should i be expecting with the 300xs? Its also very hard to maneuver
this boat. Although this sounds like an absurd question.... Any tricks for docking a boat like this?
http://img168.imageshack.us/img168/1396/dsc01010pz8.jpg (http://imageshack.us)

Thanks,
Jay

[1BadAction]

the XS is probably going to be easier to dock, just by nature of the low smooth idle that dfi engines are known for. As for performance, thats a good question. it'll be a good comparison, imo.

[Liquid Force]

Although this sounds like an absurd question.... Any tricks for docking a boat like this?

Get angry with it! thats a big boat with a single engine, most people that I have seen have trouble moving bigger boats around is because they are to timid with it in reverse.

should be really interesting to see how it goes with new school 300hp versus old school 300hp.

[wideglide55]

I'll bet it will be 10mph faster with the Merc and the right set-up,mine was.

[bulwinkle]

Gotta Ask what are you going to do with the old motor??? :)


It would look good on my Switzer...

[Mastercraft241]

it is for sale. Have a few offers so far. You could reach me at Mastercraft241@hotmail.com.

Thanks,
jay

[SUPAJAY]

The boat will feel totally different. Between the weight difference and power you will be very happy. Merc is the way to go. I HATED my 300xp:D

[Matt Gent]

The problem with docking is the setback. My friend's fishing boat has the same problem. It won't turn sharp enough because the thrust is too far from the keel.

Just gotta practice and plan ahead.

[ghost28]

when docking a boat with a lager setback such as yours jay you need to set the trim slightly positive...if the motor is fully tucked the water is jsut blowing against the transom in reverse and not doing much to control the boat....try it and you will notice a diference...there are no single engine 24 footers that are simple to dock anyway....

[kimswang]

I wonder if a race car would be faster if you lower the displacement and take out two cylinders.... Sure it will...:D

Weight of the OMC = 531 lbs
Weight of the Merc = 505 lbs

A reduction of aprox 1% total boat weight. However, I'm sure it will be more fuel efficient, smoke a lot less and be more reliable though. Can't wait for the number comparison in speed - very interesting. Best of luck with it.

[neveredge]

If the merc has the torque master gearcase it will be faster than the V8 just because that LWP on the V8 case is causing enormous drag and slowing the boat down.

A boat that big that isn't running in the 80's does not need a LWP case. My guess is that if you switched to a V6 gearcase without a cone you would pick up several mph.

The 300XS makes more HP than a stock GT300 does. A stock GT300 makes about 290 at the prop. The 300XS should be closer to 310 hp. So the 300XS should be faster.

Now if you are talking a non stock GT300 then the 3.2 merc cannot keep up. Taken to the extreme the V8 will destroy the V6. That is assuming that you could mod the opti, or just convert it to EFI.

The V8's can easily be turned into a true 400 hp motor and still run on pump premium gas. Any V6 at 400 hp is running race fuel only and spinning to many R's to be considered a lake motor.

The Merc is going to get outstanding fuel economy compared to the V8. I will bet that you will get at least double the fuel mileage.

I sent you an email about the motor, did you get it?

[Big Johnson V8]

Sure the V8 smokes alot and doesnt idle very good, the carbs drain fuel when trimmed all the way up. But they are torque monsters, with slight mods they will run with just about everybody on the lake. they only smoke when at idle or starting. I dont consider the V8 to be drag racer. I do love the Indy car sound and awesome mid range to top end power they put out. Questions is you can pick up V8 for around 3,000, have it completly rebuilt with some mods for 6,000 to 8,000 = 11,000 or you can spend 17,000 or more on a 300XS. Which one will last longer? Its seem like mathematical you could build the V8 twice for the same amount money.

[Mastercraft241]

Thanks for all the replys so far. Neveredge, i still did not get an e-mail from you... don't know why:confused:. Try again, ill be more then happy to reply. If i were to get a 300xs what exacly would i be getting? Left handed or right? spinning in or spinning out? Would i need a totally different prop?

[Airboater]

What are you trying to gain by swapping motors

[koolmatt]

jay get that motor running tits, then work it, i know you spent a lot a lot of money on the boat already why the hell would you put another 17g's into it? but thats just my opinion

[Mastercraft241]

What are you trying to gain by swapping motors
Simple... Reliability along with peace of mind.:rolleyes:

[Big Johnson V8]

Simple... Reliability along with peace of mind.:rolleyes:
Bottom line what are you looking for. If you want speed keep the V8 or go with 300. If your talking dollers the V8 will be cheaper to work on and the 300 at 17,000 is alot of money to put into a used boat. My fishing buddies say if you want reliabilty go with a big Suzuki or Yahmaha ( most water patrol and DNR use them ). Believe me I have weighed the same decision that your making. Nobody ever brings up the big E-TEC ??

[Mastercraft241]

E-tech doesnt even make 300's. The merc is the only logical choice right now. Reliability, gas efficent, and powerful. As for investing 17k into the boat. I can tell you im way past that mark. More then you'll ever know.:o

[Airboater]

You need to send that motor to monty and save yourself some $$

[1BadAction]

well i see the omc guys turned this thread ignorant real quick...

[PICKLEFORK STUD]

i got no problems with the mercs they sure make me a hell of alot more money than omc's. they seem to always break more and have more trouble than omc. i'd say in this area at a rate of about 20 to 1 that means more green for me so let me say just keep on buying those mercs so i can afford my fantastic lifestyle they have afforded me over 20 plus years. black is surely beautiful and makes me alot of green.:D :D :D :D :D :D

[kimswang]

i got no problems with the mercs they sure make me a hell of alot more money than omc's. they seem to always break more and have more trouble than omc. i'd say in this area at a rate of about 20 to 1 that means more green for me so let me say just keep on buying those mercs so i can afford my fantastic lifestyle they have afforded me over 20 plus years. black is surely beautiful and makes me alot of green.:D :D :D :D :D :D

Although most of us with some experience know this for a fact, lets support him in his moves to make us some more $$$, so the wealth will be spread and we can all enjoy our boating. And some lucky entusiast will get his hands on his old V8 and have a lot of fun with it.

[stylishskier]

well i see the omc guys turned this thread ignorant real quick...

I think what is possibly ignorant is thinking that a 300xs is the answer to this boats setup/speed issues... what is the 300xs going to gain him on this boat, other than improved fuel economy? His 300 has lasted this long, sending it out to be worked would increase his performance at a much cheaper cost than the 17k+ for new outboard+controls and rigging etc... Im pretty neutral as black and white goes, but I don't think many logical people recommend an engine that expensive on a boat such as this...

[Mastercraft241]

Although most of us with some experience know this for a fact, lets support him in his moves to make us some more $$$, so the wealth will be spread and we can all enjoy our boating. And some lucky entusiast will get his hands on his old V8 and have a lot of fun with it.
Look... i love my v8, the things a beast but its just not reliable and as for the comment about putting a motor on a boat such as this. Your comment was out of place and i really don't appreciate that. This is not a merc vs. omc thread so those of you who want to fight about it; take it somewhere else. If anyone has a suggestion of torquemaster vs sportsmaster please share your opinions. I have already spoken to lightspeed and it looks like he'll be doing the rigging.

Thanks,
Jay

[kimswang]

I don't think many logical people recommend an engine that expensive on a boat such as this...

Would he have any more fun / better investement in buying a new boat?? Didn't think so! Let him try it if he wants to and I wish him all the best... No doubt it will cost him 5 years worth of fuel and a rebuild by Monthy on the V8, it is his choice. Some of us know for a fact he will regret it, but he has to get the experience himself. After all, what is the definition of a boat?? A hole in the water you pour $$$ into, right?

[kimswang]

Look... i love my v8, the things a beast but its just not reliable and as for the comment about putting a motor on a boat such as this. Your comment was out of place and i really don't appreciate that. This is not a merc vs. omc thread so those of you who want to fight about it; take it somewhere else. If anyone has a suggestion of torquemaster vs sportsmaster please share your opinions. I have already spoken to lightspeed and it looks like he'll be doing the rigging.

Thanks,
Jay


Not fighting you here mister, rather supporting your decision. Experience is what boating is all about. I have wished you all the best before , and I will do it again. I would be the neighbor spending the night rigging it for you if you where close enough. I am anchious to see the number comparison and as stated in several posts, I support your decision. I am in no shape or form associated with neither Merc or BRP. I was sponsored by Suzuki in outboard racing in Europe as well as road racing where I won the European championship. Make no mistake about it, the gentleman that suggested Suzuki for reliability was dead on the money. This is not about that though. It is more about feelings and about having a good time on the water as well as using your mechanical skills to make your equipment work. With that I wish you all the best with your choice of replacement.

[stylishskier]

If anyone has a suggestion of torquemaster vs sportsmaster please share your opinions. I have already spoken to lightspeed and it looks like he'll be doing the rigging.

Thanks,
Jay

seems like if you're running less than 80, its not usually recommended to run a coned unit at all... so you're probably better off with the TM case. Good to hear that LS is doing the rigging, seen some of his posts, he does sweet stuff:cool:

[Big Johnson V8]

Good luck with the rigging, keep us posted on the performance. I know it was a major decision, all of us want good reliable power I hope it works well for you.

[Racemore]

Get Real,I know the V8 is a little old and maybe the thought of trying something new is your answer to your problems but the reality is the big POS gearcase on the V8 takes away from the mph.The setback is a little far for handling and speed.Too many variables.I can go to my friends Merc shop and see Mercs of every type with something blown up.I 'm sure the omc dealers my have the same problems but I'm not seeing it.The gear case on a v8 will not be your best performance case.If you look around your upset outlook you might find an alternative.Jack Barsh has been high points champ 2 years in a row(unlimited).Omc is the world outboard speed record holder.they do it with different cases.Jack runs a merc case and I won't guess the hp but it's 500 at least.
I like Mercury's and Omc's and each have problems.Maybe make an adapter plate and try a merc case,pump that big 8 up a little(not with land& sea heads)or go through a 20K motor swap and maybe get lucky.They all blow up.I'm not wanting to upset you or tell you what to do but be objective.good luck.

[scalywag]

Just bring it to "Lightspeed" and he will dial it in for ya........
Depending on how many times you boat in a week. :rolleyes:
The gas savings will equal around $80 a week......x 4= $320 per month.
The gas savings will pay the note on the 300xs.........and you will have
reliability and more speed. Plus warrantee.....
Good luck with it.
Tell us the speed gains when your done?

[Riverratt]

The gas savings will equal around $80 a week......x 4= $320 per month.
The gas savings will pay the note on the 300xs.........
That would be true if you could boat in New York 52 weeks out of the year but lets be more realistic.

[beer30]

That would be true if you could boat in New York 52 weeks out of the year but lets be more realistic.

It is at least a 1600 to 1700 a year saving, boating 5 months of the year, which is realistic estimate. :) Chuck

[Riverratt]

It is at least a 1600 to 1700 a year saving, boating 5 months of the year, which is realistic estimate. :) Chuck
That is still only $8500.00. That won't pay the note for the 300xs. Now after 5 years the motor is out of warranty and needs rebuilt. Don't get me wrong I am all for the 300xs. The V8 is a pig when it comes to fuel but they do have something about them that you gotta love. If you have the money go for it but just keep in mind if you want to sell the boat in a year or 2 you now have over $30,000.00 invested which you will not get back. Good luck with your decision.

[Mastercraft241]

Was it added that the v8 is taking premium and if im not mistaken... the 300xs takes regular?

[Airboater]

What kind of speed is that V8 pushing that big boat ,any mods to the motor.

[beer30]

That is still only $8500.00. That won't pay the note for the 300xs. Now after 5 years the motor is out of warranty and needs rebuilt. Don't get me wrong I am all for the 300xs. The V8 is a pig when it comes to fuel but they do have something about them that you gotta love. If you have the money go for it but just keep in mind if you want to sell the boat in a year or 2 you now have over $30,000.00 invested which you will not get back. Good luck with your decision.

Maybe I am wrong here, but doesn't the 300XS cost 16500? :confused: Boating all year, it could pay for its self in 2 years!!!! ;) Am I missing something here???:) Chuck

[Riverratt]

Maybe I am wrong here, but doesn't the 300XS cost 16500? :confused: Boating all year, it could pay for its self in 2 years!!!! ;) Am I missing something here???:) Chuck
You stated earlier you would save between $1600 to $1700.00 per year in fuel. At $1700.00 per year savings it would take 10 years not 2.
Chuck the over $30,000.00 comment was from the owner claiming he already has over $17,000.00 ivested in the boat before the motor.

[CRMERC]

I am not a big fan of the one big engine idea. Your boat is 24 or 25 feet long which makes it just a little to big for a single. You could get a set of used 200 merc or johnson fishing motors add a set back bracket and still not spend 17k . The twins would be ten miles an hour faster and use less fuel than the v8 for the same speed. No exotic parts or computer crap just a much faster boat out of the hole and it would much better around the dock.

Just my .02 cents feel free to call me crazy.:)

[lilabner]

I have had a V8 for 17 years..in fact had 5 of them..and I never used more than 30 gals an hour WOT..thats 6700 rpms..with fuel flow gauges and big carbs..The Merc certainly can't be that much better on fuel to pay for itself in 2 years..from seeing the Mercs around here, they won't run 2 years..todays Mercs are nothing compared to the old 50-60's inlines..they were the best outboards ever made when it comes to reliability..I can take my 22 Velocity out and run about 2 hours and use about 20 gallons..you can't run WOT all the time, you might want to but it don't happen..

[stylishskier]

Was it added that the v8 is taking premium and if im not mistaken... the 300xs takes regular?

I believe you are mistaken... 91 octane minimum req'd by the XS...

also... no 5 year warantee... 2 year limited for rec. boating according to merc racing website
http://www.mercuryracing.com/products/consumeroutboards/optimax300xs.php
by the way, I'm not trying to sway you anymore, I don't care either way, but as stated the gas savings won't pay for it alone... you might not see much performance increase and you'll have a huge hole in your pocket... more performance might be able to be had elsewhere, but the XS is a sweet motor:cool:

[Wizard]

Interesting thread. :rolleyes:

I have one of the very first 300XS's to roll of the assembly line. I have to tell you it's one of the finest motors I've ever owned over the 30 years I've been boating. Not only is it miserly on gas and oil but it's smooth idling and has obnoxious low end grunt and mid-range acceleration. Did I mention it's miserly! It burns exactly half the gas my 225EFI did on any given outing. HALF! So my bet is it will burn 1/3rd the gas of that big V-8! It's a superb engine.

As for set up on that big boat definately get the torquemaster with 1.75 gears and run a big Bravo I probably in 24p. If you get dual PVS plugs drilled into the Bravo you can adjust the holeshot. My bet is you can turn that 24 to 6000 where the XS makes peak power. Your speed will be right around 70 to low 70's depending on load.

Dump the dinosaur and get yourself a new DFI. I guarantee you will not regret it. :cool: :D

[Pro300x24LD]

Interesting thread. :rolleyes:

I have one of the very first 300XS's to roll of the assembly line. I have to tell you it's one of the finest motors I've ever owned over the 30 years I've been boating. Not only is it miserly on gas and oil but it's smooth idling and has obnoxious low end grunt and mid-range acceleration. Did I mention it's miserly! It burns exactly half the gas my 225EFI did on any given outing. HALF! So my bet is it will burn 1/3rd the gas of that big V-8! It's a superb engine.

As for set up on that big boat definately get the torquemaster with 1.75 gears and run a big Bravo I probably in 24p. If you get dual PVS plugs drilled into the Bravo you can adjust the holeshot. My bet is you can turn that 24 to 6000 where the XS makes peak power. Your speed will be right around 70 to low 70's depending on load.

Dump the dinosaur and get yourself a new DFI. I guarantee you will not regret it. :cool: :D

I would tend to lean this way for more trouble free boating....typically (and not always true) the newer the better, the newer more reliable....if you got the cash and the inkling to spend it do so....

[Pro300x24LD]

Interesting thread. :rolleyes:

I have one of the very first 300XS's to roll of the assembly line. I have to tell you it's one of the finest motors I've ever owned over the 30 years I've been boating. Not only is it miserly on gas and oil but it's smooth idling and has obnoxious low end grunt and mid-range acceleration. Did I mention it's miserly! It burns exactly half the gas my 225EFI did on any given outing. HALF! So my bet is it will burn 1/3rd the gas of that big V-8! It's a superb engine.

As for set up on that big boat definately get the torquemaster with 1.75 gears and run a big Bravo I probably in 24p. If you get dual PVS plugs drilled into the Bravo you can adjust the holeshot. My bet is you can turn that 24 to 6000 where the XS makes peak power. Your speed will be right around 70 to low 70's depending on load.

Dump the dinosaur and get yourself a new DFI. I guarantee you will not regret it. :cool: :D

I would tend to lean this way for more trouble free boating....typically (and not always true) the newer the better, the newer more reliable....if you got the cash and the inkling to spend it do so....

[Pro300x24LD]

Interesting thread. :rolleyes:

I have one of the very first 300XS's to roll of the assembly line. I have to tell you it's one of the finest motors I've ever owned over the 30 years I've been boating. Not only is it miserly on gas and oil but it's smooth idling and has obnoxious low end grunt and mid-range acceleration. Did I mention it's miserly! It burns exactly half the gas my 225EFI did on any given outing. HALF! So my bet is it will burn 1/3rd the gas of that big V-8! It's a superb engine.

As for set up on that big boat definately get the torquemaster with 1.75 gears and run a big Bravo I probably in 24p. If you get dual PVS plugs drilled into the Bravo you can adjust the holeshot. My bet is you can turn that 24 to 6000 where the XS makes peak power. Your speed will be right around 70 to low 70's depending on load.

Dump the dinosaur and get yourself a new DFI. I guarantee you will not regret it. :cool: :D

I would tend to lean this way for more trouble free boating....typically (and not always true) the newer the better, the newer more reliable....if you got the cash and the inkling to spend it do so....

[Racemore]

I would tend to lean this way for more trouble free boating....typically (and not always true) the newer the better, the newer more reliable....if you got the cash and the inkling to spend it do so....

YOU ARE LEANING 2 TIMES MORE THAN YOU NEED TO THERE TRIPPLE POST.:D :D :D

Now on the Wizard's post.A good fishin boat runs 70 and turns bravo props.I'm thinkin he is surface piercing so it seems he would run a sportmaster and a 30-32 pitch wheel.As far as octane i don't recall the compression on a stock V8 but they will run on the same gas as an old lawnmower.:cool:

[stylishskier]

YOU ARE LEANING 2 TIMES MORE THAN YOU NEED TO THERE TRIPPLE POST.:D :D :D

Now on the Wizard's post.A good fishin boat runs 70 and turns bravo props.I'm thinkin he is surface piercing so it seems he would run a sportmaster and a 30-32 pitch wheel.As far as octane i don't recall the compression on a stock V8 but they will run on the same gas as an old lawnmower.:cool:

I dont think he's cracked 70 yet???

[Racemore]

I dont think he's cracked 70 yet???

Probably not.He's got so much setback it's hard to tune the engine height because trimming the boat compounds the angle of the boat to trim angle over say a 15" setback and thats important for getting the most out of a surface setup IMO.

[stylishskier]

Probably not.He's got so much setback it's hard to tune the engine height because trimming the boat compounds the angle of the boat to trim angle over say a 15" setback and thats important for getting the most out of a surface setup IMO.

well whats the general formula you guys use? isn't it like half inch up for 6 inches back? Is it more or less than that... could be burrying that engine way deep with that setback, I mean 2" under the pad back that far has got to be near 3-4 inches??? Probably doesnt need a surfacing setup on a heavier boat like this, but probably needs to be able to go up more? Hopefully lightspeed will get him on the right track, new engine or not!

[Pro300x24LD]

wow I was really leaning....don't recall any reason why a triple post woulda popped up LOL

[Big Johnson V8]

I burn about twice the amount of gas then my brothers modified 2.5 so I know about using gas. A typical day at the lake, 75.00 truck fuel, 90.00 boat fuel then top on top of that oil at somewhere in the 30.00 a gal range. Base your choice on first performance, second reliabilty, third cost. Get the one that performs best, reliabilty will come with how YOU treat it, cost is what you feel you can afford. If you base your choice on how much gas your going to use, I heard they have some really cool sailboat on Ebay. with 9.9 on......all weekend long on 2gal of reguler.:p

[kimswang]

This info directly out of latest issue of Sport Fishing Magazine:


The carbureted 200s weighed 404 pounds each and featured 2.5-liter blocks. At 4,000 rpm, they produced 27 knots at 22 gph.
The direct-injected 200s weighed 507 pounds each and featured 3-liter blocks. At 4,000 rpm, they produced 29 knots at 18 gph.
The four-stroke 225s weigh 580 pounds each and feature 3.6-liter blocks. At 4,000 rpm, they produce 27 knots at 18 gph.It will take you 50+ years of normal boating to save in on the fuel if these guys are correct with their testing.

[kimswang]

Just my 2c...

[kimswang]

well whats the general formula you guys use? isn't it like half inch up for 6 inches back?

VERY close to 1" up for every 8" of setback at 70MPH as measured last week.

[Wizard]

Hate to disagree but the Sporty will slow that boat down. Anything under 80mph a Sportmaster is useless. Besides that heavy hull needs a bunch of leverage to get the hull free and flying. He's doing alot of it now through setback which I agree is a bit too much. The sportmaster needs to be run with the propshaft even with pad/keel to reduce the drag of the long case. I can't see any prop running even and lifting that hull. Heavy V hulls need the torquemaster which has a shorter case and runs below the bottom of the boat.

If that rig were mine I would dump the setback plate and run a Bob's 10" hydraulic jack with the 300XS toruemaster gearcase with 1.75 gears.

[Pro300x24LD]

I agree and disagree....I know it si different, but I just got off the phone with Progression. We were talking about the setup on my boat.

I agree, torquemast over sportmast.
I agree, prop even iwth bottom of boat to high (my situation) though I can still carry it.
I disagree on 10" of set back, I have a lighter boat of similar size and run 16.5 before vacuum bagging they used about 25" if I understood kevin right. My point is that boat is the same length but heavier then my boat, He will need more then 10"

Lightspeed is no dummy, if that is who is going to set it up, it will be set up properly and run pretty good IMO

[Mastercraft241]

Just brought it to East Coast Marine a couple hours ago. Looks like im putting on the 300xs with a 1.75 torquemaster with the heavy duty ram steering. Ill keep you guys updated on the speed changes. Right now... im going 60.5 with a full tank of gas and 2 guys (180lbs and 200lbs).

[Dirk Pitt]

Just brought it to East Coast Marine a couple hours ago. Looks like im putting on the 300xs with a 1.75 torquemaster with the heavy duty ram steering. Ill keep you guys updated on the speed changes. Right now... im going 60.5 with a full tank of gas and 2 guys (180lbs and 200lbs).

Im glad to hear your having a pro do this job, you will be amazed at the work EastCoast will do, and the attention he will give as far as your setup......
Most important he wil spend hours of testing to get the right setup,
Great choice, in motors and riggers!!!!:D

[Dutch]

and by going to East Coast you will have it back in a decent amount
of time. Another guy from LI has his boat at another shop for a re-
rig, and it's been there since November, and still has a few weeks to
go.:(

[Dirk Pitt]

and by going to East Coast you will have it back in a decent amount
of time. Another guy from LI has his boat at another shop for a re-
rig, and it's been there since November, and still has a few weeks to
go.:(

I wonder who that is?:rolleyes:

[Mastercraft241]

Got my boat back from east coast Marine today. It looks and runs amazing. So glad i switched to the 300xs. I've run it for a little over 2 hours today hitting 4000 rpm and switching it up every couple mins. Usually sticking from 3k-4k. Im told to keep doing this for 10 hours, which i will. Boat seems a lot more stable then it did before. Joey at east coast did an amazing job, unbelievable actually. I would recommend him to anyone.:D

[tigweld]

cool, what prop are you runing? Let us know how it runs.:D

[Pro300x24LD]

Good deal, I bet you get close to a 10 mph increase

[WILDMAN]

As far as break-in, the sticker right on the motor says to keep it 4000-5400 rpm for the first hour and don't let it idle for over 5 minutes. I believe the ten hour thing is more like a Yamaha thing. I've put a 300xs on a couple new 24ft Checkmates. I've seen 74.8 running light and around 70 with 3 people and 30 gallons of fuel. If you have a couple hours on it, let it rip!

[Mastercraft241]

wildman, you sure man? I've put 3 hours on it keeping it 4k and under so far. Also for the previous questions, i have a 21 pitch rev 4 on it right now. Working great so far :) about to head out right now

[themdshrk69]

As far as break-in, the sticker right on the motor says to keep it 4000-5400 rpm for the first hour and don't let it idle for over 5 minutes. I believe the ten hour thing is more like a Yamaha thing. I've put a 300xs on a couple new 24ft Checkmates. I've seen 74.8 running light and around 70 with 3 people and 30 gallons of fuel. If you have a couple hours on it, let it rip!well my 300 johnson on a 21 checkmate hits 78.4 best on gps with just me and 75 with the wife on board:eek: :D

[WILDMAN]

wildman, you sure man? I've put 3 hours on it keeping it 4k and under so far. Also for the previous questions, i have a 21 pitch rev 4 on it right now. Working great so far :) about to head out right now

I'm positive. I've had 14 of them so far. They all say it right on the breakin sticker. 4000-5400 for the first hour. The computer will double oil it for 4 hours. I recently "broke in" a 25 Liberator at 85-99 mph. 99 was at the 5400 rpm. The motors are run about 1.5 hours before they are even crated up.
HAMMER IT!!

[gotboostedvr6]

i demand pics on trailer and in water.

bikinis on the boat are good 2

:)

[ghost28]

i have seen it in person a few times recently...looks great...jay is right about the job eastcoast did...i can not wait to see it run.....

hey jay you coming out to tanner tomortrow????

[gotboostedvr6]

still running the same setback?

[koolmatt]

i demand pics on trailer and in water.

bikinis on the boat are good 2

:)


i agree!! jay hopefully for your b day tomm someone buys you a camera so i can see the boat finally, and yea you need some pics of the pu tang on the boat especially that freaky chick aka your gf :p but please no pics of that girl who you were trying to tell me about i think everyone would throw up..... also when ever you want to race my uncles ls-7 let me know lol

[Mastercraft241]

i have seen it in person a few times recently...looks great...jay is right about the job eastcoast did...i can not wait to see it run.....

hey jay you coming out to tanner tomortrow????

Thanks everyone. I might be comming out to tanner today but its going to be hard considering its my birthday. And wildman, i did floor it a little yesterday... that thing has some unbelievable torque. Boat got real loose on me and i had to back off. I'll get some pics today for you guys :D

[gotboostedvr6]

Happy b day


waiting on pics :)

[ghost28]

Happy Birthday Jay...............

keep us posted on the #s....

hey jay...i need to borrow that 21 Rev 4 one day for a quick blast to see if my boat can swing it....i have a 19 on it now and its hitting the limiter pretty hard....i dont wanna buy one without trying one first to be sure....

[Mastercraft241]

Ghost, if u want, you can come get it today and try it out at tanner since i wont be able to make it out today (birthday and extreme sunburn). Give me a call at 516-225-3553.

[ghost28]

sunburn????you too....spent the day messing around in the yard here at my house and man oh man...i am roasted....

i would come by and get it but i am still working...i may escape fo a couple of minutes to take a buzz by tanner and see if anyone is out....

we will meeet up one of these days....

[lilabner]

So what are the results? How fast..how much fuel..comparison..:)

[150aintenuff]

dude ya have had a month.... results already....

[Mastercraft241]

ha, sorry guys. I've had a net gain of 8mph. I was pulling 60mph with me and half a tank of gas with the v8 and i've pushed 68 with the 300xs. I was burning somewhere between 12gph and 16gph cruising with the v8 and im burning around 8gph with the merc. I've put 44hrs on the merc in the past 3 weeks and haven't had a problem yet. Switching from the V8 to the merc was by far the best decision I've made with this boat.:D

[150aintenuff]

dats nice.... 8GPH at what speed.....

[Mastercraft241]

not constant speed. Varying between 43-53mph (half a load). Thats about 4500rpm to 4950. Around here though, you dont have much areas that you can literally run for an hour without hitting a 5mph zone... so factor in a little of that too

[bigboy]

Wow, thats a big difference! You gained more than 10% of speed.
How does she accelerates? Better than the V8?

[NicePackage]

My boat is 1/2 the size of yours and you have 1/2 the fuel consumption. Sounds like an awesome choice, 8mph is a significant difference as well.

[Riverratt]

Your first post on this thread says you got 66 with the Johnson:confused: Now you say 60

[Mastercraft241]

Your first post on this thread says you got 66 with the Johnson:confused: Now you say 60
According to the previous owner in florida, he said he was getting 66gps. Down here and in arkansas the fastest we pushed it was 60.2 :eek:

[beer30]

Your first post on this thread says you got 66 with the Johnson:confused: Now you say 60

Ralph does not like it when a Merc outperforms an OMC.:D :D ;) Chuck

[99fxst99]

I am not a big fan of the one big engine idea. Your boat is 24 or 25 feet long which makes it just a little to big for a single. You could get a set of used 200 merc or johnson fishing motors add a set back bracket and still not spend 17k . The twins would be ten miles an hour faster and use less fuel than the v8 for the same speed. No exotic parts or computer crap just a much faster boat out of the hole and it would much better around the dock.

Just my .02 cents feel free to call me crazy.:)

CRMerc, I tend to agree. I had a 25' Seebold Eagle single 330hp Mercruiser, 54-55mph. Put a pair of BONE STOCK 2.4L 200hp Mercs on it and went to 72mph immediately. Turned the props inbd and went to 75-76mph. A twin engine boat is more fun to drive, and handles well at low speed around the marina (especially if you leave the props turning outbd). The only time I hurt an engine I was totally to blame, and I had the other engine to come home on. I used 25" motors which allowed me to forego the long offset bracket and use Bob's 5" jacking plates, and still be able to tilt the engines. Mastercraft, I have liked that boat since it was intro'd in the 80's. Don't let anyone talk you out of doing anything you want to it. If we were all logical, no one would be fast boating!! Good Luck!!

[1BadAction]

and theres twice the rigging, twice the gearcase drag, twice the maintenance, twice the props to have worked, etc etc.

like anything there is trade-offs.

[Airboater]

Are you running the same pitch prop you had on the V8 and what rpms were YOU turning it and the new motor .

[Instigator]

Not casting stones, we all know the XS is far surperior to a 20 yr old 2 stroke anything.

I expected simialr speeds but far surperior fuel efficincy.

The 300 V-8's were pretty close to a true 300 HP's and I think I've read that the XS's are 300 or a bit more??

I think the XS is very close in weight to the 8's 550 lbs too if not a bit more ??

That being said how did we get 6 MPH's??? The 8's l/u is crap but 6 MPH worth??

To gain 6 MPH's in a boat that size and weight I'd guess you'd need closer to 60+ more HP to do it.

More likely the 8 was weak and or out of tune maybe??

Same installed heith and set back??

Regardless, congrats on your new motor.

Huge improvemenet in fuel consumption plus 8 MPH's ???

Don't get much better than that.

Gary

[bigboy]

Maybe it has some more torque which results in higher speeds and especialy because it's a heavy boat?

I'm just guessing around so dont shoot me:D

[150aintenuff]

not constant speed. Varying between 43-53mph (half a load). Thats about 4500rpm to 4950. Around here though, you dont have much areas that you can literally run for an hour without hitting a 5mph zone... so factor in a little of that too

very respectible..... that would be half of the fuel my 150 carb uses at the same speed... not to shabby..

[Mastercraft241]

Not casting stones, we all know the XS is far surperior to a 20 yr old 2 stroke anything.

I expected simialr speeds but far surperior fuel efficincy.

The 300 V-8's were pretty close to a true 300 HP's and I think I've read that the XS's are 300 or a bit more??

I think the XS is very close in weight to the 8's 550 lbs too if not a bit more ??

That being said how did we get 6 MPH's??? The 8's l/u is crap but 6 MPH worth??

To gain 6 MPH's in a boat that size and weight I'd guess you'd need closer to 60+ more HP to do it.

More likely the 8 was weak and or out of tune maybe??

Same installed heith and set back??

Regardless, congrats on your new motor.

Huge improvemenet in fuel consumption plus 8 MPH's ???

Don't get much better than that.

Gary
Hey guys, just got a new top speed today... 70.9mph :D. Very happy with the results. Instigator, i guess you can say this engine is probably propped a little better then the omc. Thats always a factor. Im turning i think 6k rpms with the merc spinnnig a 21p rev 4. I had a 24 pitch hydromotive on the omc spinning 5700rpms going 60mph.

[lilabner]

Being happy is all that counts..but your numbers just ain't gettin it..

[WILDMAN]

24ft Checkmate with a 300xs. 74.8 mph

[gotboostedvr6]

is the setback still insane?

[WILDMAN]

is the setback still insane?

Just 12"

[gotboostedvr6]

so 31" was bit much i see lol

maybe the V8 was too deep

[300x Stoker]

I still need to have someone splain to me how a V8 only weighs 30lb more than a 300V6. Plus once they're runnin the V8 would hold a lot more water. I call BS.

Wildman you've had some of these things on a scale haven't you??

With the speed diff. he's getting the weight or the power is not close.:mad:

[Instigator]

I still need to have someone splain to me how a V8 only weighs 30lb more than a 300V6. Plus once they're runnin the V8 would hold a lot more water. I call BS.

Wildman you've had some of these things on a scale haven't you??

With the speed diff. he's getting the weight or the power is not close.:mad:

V-8 = 550

Bass and Walleye did an article a while back about advertised weight vs actual and the most inaccurate was Merc.

The OMC V-6 was basically what they advertised while some off the Mercs were off by over 30 lbs.

I've not heard anyone comment on an 8's "actual" weight.

I know I can toss a 6 block up on a bench with ease.

An 8 I cannot:o

[bigboy]

24ft Checkmate with a 300xs. 74.8 mph

Looks like it needs a lot trim to make it fly:)

[Mastercraft241]

Hey guys, im not looking to make this a bash thread of v8 to mercs. Im just calling it how i see it. Theres many factors that go into speed such as prop selection, humidity, etc, etc... So far this motor is performing a lot better. Ive put 46 hours on this motor in 3 weeks. I could tell you without a doubt, theres no way i'd be able to put that much hours on my v8 without a single problem.

[Instigator]

Hey guys, im not looking to make this a bash thread of v8 to mercs.
100% agreed.

Bottom line is you are way ahead of where you were before starting this project.

They don't always turnout this good.

Nice to see it when they do :)

[Mastercraft241]

Hey guys, heres some pics from my ride today. Just went around Long Beach.. got pretty rough in the inlet, but got through it without a problem. Engines running great. I have one questions though. If i dont have the engine trimmed all the way down, im not able to start up. Then, most times.. it will take the engine maybe 15 seconds until it really starts to rev and get going. Am i propped too high here? I had a full boat (5 people) and a full tank and i wasnt able to get more then 2krpms out of the motor unless i had my tabs all the way down..... even then it was tough.:confused:
http://img530.imageshack.us/img530/9435/dsc03242ld4.jpg (http://imageshack.us)
http://img470.imageshack.us/img470/7143/dsc0278ec5.jpg (http://imageshack.us)
http://img470.imageshack.us/img470/391/dsc0317bu4.jpg (http://imageshack.us)

[neveredge]

The main reason the merc is faster is that it has a horsepower advantage. The V8 only made about 290 at the prop. Not 300 like most folks think. The Merc makes over 300, closer to 315 I'm told.

The gearcase is another big difference. That particular V8 had a LWP mounted on a V8 gearcase. This is a big no-no on a sub 85 mph boat. Massive drag penalty compared to the torque master on the Merc. That alone could cost 8 mph.

Screamandfly did a test a few years back of a sporty and a torque master on a sub 85 mph boat. The TM was several MPH faster than the sporty.

The V8s really only shine when they are modified. A very mild hop up with an EFI set-up and the merc would get smoked.

Taken to it's limit the V8 is capable of astonishing power output, far more than the Merc 3.2 can ever achieve.

If I had the money I would buy that V8 and show you just what it can be. Maybe someday I will.

[kimswang]

The gearcase is another big difference. That particular V8 had a LWP mounted on a V8 gearcase. This is a big no-no on a sub 85 mph boat. Massive drag penalty compared to the torque master on the Merc. That alone could cost 8 mph.

The V8s really only shine when they are modified. A very mild hop up with an EFI set-up and the merc would get smoked.

Taken to it's limit the V8 is capable of astonishing power output, far more than the Merc 3.2 can ever achieve.

The reason I am hangin on to my V8's right there.... I will send them out and have the MAD EFI one day...

[Mastercraft241]

That alone could cost 8 mph.
thats an absurd statement. More along the lines of maybe 2 or 3mph. Very happy with the merc though. Ran the boat for 4 hours today and burned only 21 gals... couldnt be happier :D

[kimswang]

thats an absurd statement. More along the lines of maybe 2 or 3mph. Very happy with the merc though. Ran the boat for 4 hours today and burned only 21 gals... couldnt be happier :D

Glad you are happy with it, and I bet the fuel saving is awesome. Not an absurd statement from NE by any means, here is the formula: D=V2xAx1/2DxCd. Hence the reason why I am running non LWP on my three V8's... Until I pass my goal of 88+

[150aintenuff]

sounds as though you need more venting in your prop.... the big mercs have a bog below 2500ish ya have to spool them up abpve that enlarge the vents on yer prop and that will go away.

[NNT]

WOW! 8 mph is awesome, I can't wait till you get to tweak the setup even more http://forums.screamandfly.com/forums/images/icons/icon14.gif

[neveredge]

thats an absurd statement. More along the lines of maybe 2 or 3mph. Very happy with the merc though. Ran the boat for 4 hours today and burned only 21 gals... couldnt be happier :D


No it is not an absurd statement. The V8 case is bigger and longer in stock form and that one has a LWP on it making it even BIGGER. Underwater drag will scrub off gobs of speed.

Case in point, rrrevinrude on here had a modified Evinrude on an HST. With the OMC coned case he went 117 mph. He then put a Merc sporty on it and GAINED 10 MPH. These cases were surfaced where there is even less drag to begin with.

If big speed is what you wanted then you made the wrong choice by ditching the 8. If all around good performance with excellent fuel economy was your goal then you achieved it and then some. But the fact is if you put that TM on the 8 with EFI and a very mild hop up you would have had a much faster smooth running motor. The only drawback would have been all the fuel she would eat.

B&WBs did a gearcase test a few years back on a Stratos bass boat that ran mid 70s. The case that was the fastest on that hull was the brp lightning case. It was going against a tooters modified case. According to the experts the Tooters case should have won hands down. It didn't because of too much drag. They also tested a Yamaha where the stock LWP case was faster than a Bobs LWP case by several MPH.

So what I said is not absurd and is probabaly right on the mark.

[Instigator]

rrrevinrude on here had a modified Evinrude on an HST. With the OMC coned case he went 117 mph. He then put a Merc sporty on it and GAINED 10 MPH.

went from a 1.86 to 1.62

May have had a small effect :rolleyes:

And was running 120 on the OMC case.

I lost 3 MPH's when I put nose cones on my 80 MPH Sonic and none on my 80 MPH Laser.

[Mastercraft241]

new top speed :D

[NNT]

new top speed :D


SAWEEEEEEET!!!! I have a feeling it's just going to keep going higher :Dhttp://forums.screamandfly.com/forums/images/icons/icon14.gif

[Riverratt]

I am glad you are happy. I had a ride in a Skater with the 300xs and it is an awesome motor but your original speeds were surprising me since you originally posted that you ran 66 with the V8 and were not much better with the xs but I see it is coming around for you. If bombardier does not come out with anything in the future I may be swapping out my V8 for the xs also.

[lilabner]

If I had the money I would buy that V8 and show you just what it can be. Maybe someday I will.
If I had the money, I'd buy Las Vegas..why stop with a V8?

[lilabner]

I've never lost speed with a V8 Madonna nose cone w/LWP..never gained any either..but did gain better control and water pressure..and I've had a lot of V'8's, and still have one on a Velocity..runs over 80 at 6100..but I'm too old and chicken to stretch it out..plus I enjoy being retired in one piece..

[Bartyparty69]

Threads like this make me laugh. A new 300 merc is faster then a 17 year old v-8 with numberous hours on it. You know my 21" lcd tv has a better picture then the tv I bought back in 1990. Oh yeah, and it weighs less! Go figure. Why waste time arguing about it? lets all go fast, have a good time, and spend an obsured amout of money on gas. I will tell ya. Still love my v-8. Pushes my 21' eliminator in the low 90s. Even thought I beat the hell out of it and it has a lot of hours on it. I havnt even considered a merc. Mainly because I dont have that kind of money. (plus my dad worked for omc) Maybe someday! Of course by then gas will be $10 gal and my eliminator will probably turn into a lawn ornament. Btw the smaller gear case does make a difference. I put a v-6 gear case on mine. I could tell a difference right away. Unfortunatally the pinion gear split in half before I ran the gas tanks low enough to really run it. Maybe ill have better luck this next time. Gona wait till I have less then 10gal left before I try it.<a href="http://photobucket.com" target="_blank"><img src="http://i122.photobucket.com/albums/o255/bartyparty69/Shawano/2007/Scotts%20weekend/DSC01815.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

[Mastercraft241]

Just bought a 21p trophy... Hopfully going to pick up 300rpms which will put me a 6300rpms. This will give me a lot better holeshot and maybe even a little more top end??? The trophys going to have a smaller diameter but hopfully the rpms will make up the difference. So ghost, if you wanna try out this 21p rev 4 give me a call and ill be more then happy to let ya test it out.

-Jay
516-225-3553

[skydog]

Sweet MERC RULE!!!

[Mastercraft241]

Ran with the 21p and WOW... the acceleration on this prop is absolutely insane. I lost 6mph on the top end though... i pulled 64.8 today pulling the same rpms i pull with my 21p rev 4:confused::confused:(6050)