Hole Shot, Prop & Tach

[mattyc]

Hello!

I'm running an 87 Stratos 17'9" Bass boat with a Mariner 150 V6 on it. I've got a 14 1/4 x 24 SS prop on it right now, and I've got terrible hole shot. The engine was rebuilt 2 years ago and run on a dyno, and it was within specs -- no problems there. So, I probably need to go to a lower pitched prop.

I've got a few questions I'm hoping to get help with:

1. The book for the boat calls out two different WOT RPM ranges for this motor, 5000-5500 and 5500-6000. Apparently there were two versions of this motor, and the book doesn't tell the difference between them. How do I know which one I have?

2. I'm want to buy my prop online, but I'm seeing numbers like this (see below), and not sure where to figure out that they will work on my motor. Is there anywhere I can check online?

48-832832A45
48-75724-23

If I find a 14 1/4" prop that is for a Mariner/Mercury/Mercruiser will it most likely fit on my boat, or is this not the case? Will the correct # of splines (15 for my Mariner I think) determine if the prop will fit or not?

3. Best guesses as to what I need for a prop? A 21 or a 22...? Do I need to stick with a 14 1/4"?

[Gerben]

Hi,

Few questions to get a better picture:
What is your WOT Rpm?
What prop do you have now, any markings/nr's ?
Any setback?

What helps on many boats is a "whale tail"
(a plate that makes the cavitation plate wider)
Helps lift the transom when planing off.

Gerben

PS Fill in your profile info. Perhaps someone is nearby to let you test some props..

[Vinnie]

Matt,

My first "fast" bassboat was a 1987 Stratos 179V and a 150 Mariner Mag. My favorite prop back then was a 25 4 blade Predator. I could turn it 6000 rpm on a regular basis. The boat woul run high 60s with a light load. Did have a 5 1/2" CMC jackplate on it.

According to Stratos back then, some were lighter than others. Most of the earlier ones wwere pretty light. I could run faster than all Rngers with 150s and most others with 200.. Used to drive them boys crazy!!

Is your motor a Magnum version or regular one?

Vinnie

[mattyc]

OK -- that must be the difference. I'm running a standard Mariner 150. The 5500-6000 RPM range listed in the book must be for the Mariner Mag.

I've got a 3 blade 14 1/4 x 24 prop -- not sure what make/model , but I would assume it came with the engine...? I don't have a jackplate, and I can't afford to put a jackplate on the boat. (Are there used jackplates out there that a guy could get for less $100? This may be a ridiculous question...)

What is a "whale tail"? Is it one of those "fin" things? Any suggestions there, will a cheap one work?

My tach hasn't worked for a while, and I'm putting in a new one tonight -- so I'll report on my WOT RPMs tomorrow.

[sho305]

That is the fins you bolt to the cavitaion plate on the lower unit. When you trim down to take off they push the motor up, as you trim up they come out of the water and do nothing. They work great to get the boat up fast. Check the misc. sale thread for plates, you can get a new one from someone like Rickracer for like $130 and up.

[O/B Dude]

I have a prop that would work well on your set up. Its a 14.5 x 22 ET cut chopper, done by Aquaholic. Holeshot is great, very little slip all the way to redline. Great mid range punch and top speed. Very low steering torque and great handling. There is a picture on the buy and sell/props forum if you are interested. $285 + shipping.

You can get a manual jack plate used on this board for $90-$125. I had a similar setup as yours some years back. Ran a 22 chopper. Ran well but choppers have poor holeshot and bad steering torque.

Good luck.

[Stv Euro]

mattyc


If you can get the prop that OBdude has it should help you. That prop is built to come out of the hole and keep pulling and with it being a 22 ET it should work great. Always remember that high performance props can be trimmed high for top end without venting because of the cup that is in the prop. Well worth the money!!!

[ghind]

We still need to know how many RPMs you turn now at WOT with your normal load. Also, I assume you often run at WOT?

If you are cost conscious and you are turning minimal RPM at WOT, it may be best to have your current prop worked by a reputable prop man. If you want the best, you will probably have to buy another prop, but if you are just after a significant improvement with little investment it may be possible to work what you have.

So, how many RPM at WOT?

[mattyc]

Took it out last night for the first time all year to figure out my WOT RPMs, and... The motor would run for 10 seconds at a time. I probably started it 20 times before I figured out my priming bulb was soft. I'd pump it back up and run for 10 seconds and it would go soft. I put a new bulb on -- from what I hear, it's pretty common to have the bulb go.

Yeah, I'm usually running WOT. I fish a lot of bass tournaments in this rig, so it's usally ON or OFF!!!

I'll let you guys know my WOT RPMS tomorrow after I take it out in the AM.

Thanks.

[mattyc]

Some questions about jackplates...

What is the whole idea behind a jackplate?
Is it less cross sectional area or running in cleaner water?

I'm kinda nervous about the idea of a jackplate -- the motor's been sitting on that transom for 16 years... what could go wrong?

Also, if I'm looking at jackplates, what do I want to look for?

Thanks for the education, guys!!!

[mattyc]

Another question -- about the whale tail... would something like this work, or would I regret buying it. It's a $25 dol-fin or something like that...

http://www.basspro-shops.com/servlet/catalog.TextId?hvarTextId=27337&hvarDept=200&hvarEvent=&hvarClassCode=2&hvarSubCode=6&hvarTarget=browse

[sho305]

It your bow goes way up when you take off, and you have the drive tucked in at negative trim, the fins will help you. The only time they could be bad, is if your drive is so low that they would be in the water at high speeds. Any modern boat should not have the cavitation plate wet at anything above the lowest trim that you don't run at wot. I have used the fins, and they work-my boat "popped" out of the water on plane with it. I like the smaller ones myself, unless I had a big tub of a boat to get up. They also help some if you have a cavitation problem. Great if you pull skiers to keep the bow down. If you have a big fin on and get air, it can make the bow slap down hard on a small hull.

While the plate will get the motor back to cleaner water some, the big idea is to weight the motor back more, to take more weight off the bow of the whole boat. If you need to run lots of positive trim at wot, then the LU is pulling the stern down to lift the bow. This kills some speed. Moving the weight back some allows less positive trim so your prop/LU runs straighter in the water, and is not pulling the transom way down into the water to get the hull at the right attitude/attack angle. In this case, any setback of the motor will help some because it also gives the LU more leverage to lift the bow. You'll see on a fast hipo boat they run 0 or slight negative trim. Remember those are special hulls with lots of setup into them.

Then, you can lift the drive/motor higher in addition for more speed due to losing the water friction on the LU and using efficient surfacing props. The better balance your hull the higher you can go, most fishing boats still need bow lift from the prop and can only go maybe 3" below the pad at the higher point. That is why you see 20" of setback on some hulls to get the balance for all-out speed.

Of course you must address water supply to the motor with a low water pickup if you jack it way up, and a water pressure gauge is a must for any jack use. Going hog-wild here can hinder normal performance of a boat or ability to pull a skier. Also note you are putting more stress on your transom, so it must be strong or beefed up according to how much you setback and abuse it, motor weight, etc. You can also help out by putting the boat on a diet, moving weight to the stern, balancing it side to side, have a sharp perfect prop, etc. S&F is packed full of that good info too:cool:

[mattyc]

When you say "efficient surfacing props" what do you mean?

I talked to a guy at Stratos this AM, and he said that a 5" jackplate is a piece of cake for the '87 179V, so I feel a little better about that.

He also said that what's happening with the hole shot is that the prop isn't slipping enough to rev up to high enough RPMs to get out of the hole. By putting on a jackplate, and getting the motor higher in the water column, does that allow the prop to slip more? (And GET OUT!!!)

Thanks everybody.

[sho305]

Todays performance props surface well because you go faster that way. A jack will help you get more height than the transom to get more out of them.

Holeshot rpm is a function of the prop design and the exhaust flow over the prop hub, or vents in it. A jack might make it cavitate easier but that does not help you. Holeshot is largely a function of boat weight and setup. Most people don't like real slippy props for normal use. They can be a pain if you take passengers, and they want to break free at slow speeds or in turns. If you are just speeding around they are fine. If you are plowing bad on a holeshot, get fins on there and you will be amazed. When they push the transom up, it unwets the hull and off you go.

A 5" plate will not make a huge difference, but setback can make a holeshot worse by lightening the bow. You will see wedges for motors that give more negative trim to help this. Many hulls w/big setback and tuned for max speed have a hard time getting up, and they use a power jack often to lower it for holeshots then raise at speed.

[Raceman]

Sho, there's one other time those dol fins are bad............. when you're lookin' at the boat on the trailer. They sho' do ugly up a motor. Reminds me of an ole gal I saw with T Rex one time with real wide feet. I can't remember her name, she didn't say much, just an occasional wise quack.

[sho305]

True Raceman, but I was sneeky and got this one http://www.basspro-shops.com/servlet/catalog.TextId?hvarTextId=1100&hvarTarget=search for smaller motors. It looks pretty little on a 150hp;) I have another one like big wings on each side, ugly!

[O/B Dude]

I dont see the year of your motor listed in the post, but guys, correct me if I am wrong...he has no RPM redline issues. His motor is physically capable of withstanding 7000+ rpm but the stock tuner and carbs will keep it well below that level.

Check your transom condition. With the boat on the trailer, put your foot on the cavitation plate above the prop and put your weight on it. See if the transom flexes. If not, the transom is fine. Get a 5" or 6" manual jackplate, available used for $80-$125. Raise the motor till you lose water pressure then drop it 1 - 1 1/2" . (this is if you arent running a low water pick up cone)

Get a good prop in the 21-23 range that has moderate bow lift, and decent cupping. A bobs anti cavitation plate will help too. The doelfins are too big and ugly for my liking. This should get you much improved holeshot and better top end speed. If you want to really improve things, get a 2.4 200 tuner to wake up that 150. (I am assuming it has the long square one on it now) Get a low water pickup nose cone installed and set the shaft 1/2" below the pad to start.

If you want to go less expensive, just get a good prop that doesnt slip out of the hole and dont go heavy on pitch. I am assuming you would prefer better holeshot and top end. If all you want is holeshot, get an anti cavition plate and a good prop. A 4 or 5 blade will do it for you but will cost you top speed.

I hope this helps.

PS, if you decide you want my prop, I will throw in a 2.4 200 tuner free. It has a small chip in it but works fine. If you change the tuner, get solid mounts while you have it apart.

[mattyc]

What is the "2.4 200 tuner"???

My '87 Mariner 150 is built on a merc 2.0 block if I remember correctly...

[O/B Dude]

Your 2.0 litre is a 150 because the exhaust and the carbs have been restricted. The carbs arent as big a deal. Put a 2.4 litre 200 tuner on it and open up any restriction in the exhaust adaptor and block outlet and you will get more like 175+ hp. The 150 tuners are long and square kinda like the 2.5 200 tuners. A 2.4 200 tuner has a larger inner diameter and is bell shaped. 2.4 200 tuners wake up 2.0 litre 150's.

Good luck

[mattyc]

OK guys, I feel really dumb... I've never really payed any attention to it before, but my cowling says "Mariner Magnum". So what would you guess my WOT RPM range should be?

Like I said before the book I have on the motor calls out 5000-5500 and 5500-6000, but without distinguishing the motors...

(I called a dealer, and they had no clue... oh, so helpful ;)

What do you guys thinK? THanks!

[mattyc]

Finally got it out and working this AM!!!

I picked up one of the dol-fins and the boat came out of the hole much, much better! The engine still seems to drag a bit when I hit the throttle though...

Ran 5400 RPM with the 24 pitch prop. Had all trolling batteries, my buddy and all fishing gear in there and it did about 58 GPS. Now the question is can this motor do 6000? And in that case, I'd wanna go to a 22" right?

[O/B Dude]

Yes it can and yes you do.:)

[Doubledog]

Hey Matt. I really wish I could help you with this but I'm afraid at the time of owning mine, I barely had enough money to buy gas to buy worms & a few extra hooks. The boat was a couple years old & the motor was a year old left over still new in crate. I had saved for two summers of mowing grass & picking pea-nuts just enough for a good down payment. But I had a killer bass rig that was not only good looking, but fast.

My engine was the 2.4 Mag II. Running a Laser II prop (not sure what pitch), 6" setback, & I remember she was raised pretty high. I think the most I wound her out was a couple times over 6k, but just for a moment. I was too afraid to hurt it due to not having the funds to fix it just in case.

Holeshot with two people & gear was good. Top end was pretty good too. Speedo would read 72-75 all day but I'd say the closest I came to a real speed was when my buddy with a Vector & 235 Johnny that had been radared & had some tournament waterski airgauge speedo, said that I was running in mid 60's.

You've got to take yourself back to being a teenager now with all that talk.

Someone wrote in the top about burning Rangers with 200's. Those guys would see a 'kid' backing down a bass rig with no 'Daddy' around & jaws would drop. I loved it. I'd catch them heading across the lake & catch up to them & just generally have a good time. Problem is, I was & still am skinny & the steering torque killed my arms big time. Anything trimmed neutral or tucked & under 50 was fine. She'd fly straight all day, but give it some trim & the torque would whoop you. Chine walk was fine after I learned to drive through it & not be so afraid.

I was wanting to experiment with a High5 at the time because it looked cool, had I known then what I do know, I'd have picked up a good four blade & bought hydrolic steering.

We also skiied the hell out of that boat. Very fond memories. Sorry for rambling & I know this didn't help any but it sure was great to think back.

Jamie

[mattyc]

Hey, sounds like you've got a few fond memories of that boat! My story is similar -- I got the boat just two years ago, in my last year of college, spent every penny I could find to drop $3800 on the rig. And I FINALLY had something I could get around in and at least compete with other guys.

But the last two years of sending my buddies up to the front of the boat just so I could get her out of the hole have gotten a little old!!! I know this rig can get up quick and run fast, so here I am learning all I can from you guys here!

Thinking about a jackplate on my rig, there's something I've been wondering about... Everywhere I read about jackplates, I read about low-water pickups. What is this? Just a lower water intake?

Also, what is a nosecone, and what is the purpose?

I think I understand the whole idea behind a jackplate now. That is -- putting the center of gravity back farther which helps get more of the boat out of the water (correct?), allowing the motor to be more vertical, thus moving through the water more efficently.

Someone mentioned earlier in this thread that putting a jackplate on my boat may make it more difficult to get out of the hole. Well, if I go to a 22P (instead of my current 24) and have the whale tail on there, it should pop me out of the hole. At this point will the jackplate help me to GO FAST?

If I may ask one more question here, I'd like to (really, thanks for the education guys!!!). I've seen a lot of "chopper" props here. From what I gather, it seems that they are made to run partially out of the water? True? How and why do they work better than a standard prop that I have on my boat?

THANK YOU!!!

[sho305]

The LWP, low water pickup is in the bottom of nosecone so you can jack the motor higher. Above about 60mph a nosecone helps the LU cut the water better, but telds to not work as well on anything needing bow lift. In flowing the water over the LU better you loose bow lift, so that hull will get wet and go slower. It works ok as you need to run the prop lower for bow lift anyway; so you don't need one with those hulls. Lots of grey area there though.

Some setback should not hurt holeshot badly, and it balances the hull at high speed. If you run lots of trim then, it will help you. If you get over say 6" then it makes the bow come up even more on holeshot. You would need the fins on the LU or maybe negative transom wedges in the motor/jack. Props change holeshot too.

The props, basics are the big cloverleaf stock round ear that works best under water. Then the chopper small and large round ears. The larger more under water but will surface without blowing out like stock props. The small ear better at surfacing. The Clevor is great surfacing but sucks in the water and will not work well to push any weight up on to plane. All give and take, whatever works best on your combo.

[Doubledog]

Sho is right on.

My boat had terrible bow rise also, but thats typical for that style boat. You either get used to it or buy a plaining aid.

I kept it for a little over four years & the only thing I did was replace the plugs & put a carb kit after letting it sit for too long. Never a lick of trouble.

Getting to the jack plate, the guys at the marina I bought it from reccommended it highly along with the top of the line Laser II (then).

Don't think about a nose cone for that boat. You get in the high 70's to low 80's then maybe. You need to keep some prop in the water to get bite to hold the bow up. You're talking about hole shot, to get a decent one, you'll need to keep it pretty low & raise for top end.

The boat is very well built (a little on the heavy side) & I wouldn't go with an over hub style prop. Generally those props don't work well till you get on the top end. You think your hole shot suffers now, put one on & watch what happens. On a lighter rig, their fine.

Try to find you a good four blade Trophy. You can pick them up here & the guys will take care of you on the $$$. Plus the four blades will help you with hole shot, give you less steering torque and be a great all around prop from what I've read over the years.

My .02 is to enjoy what you have. Search for a four blade, maybe a 6 inch setback to help hold the bow at speed, & don't put a dorky whale tail on it. Build one like Vector Mike did out of pressed (checkered) stainless steel.

Have fun brother & keep me posted.

[ghind]

I'd say start with the jackplate then the rest. Unless you have another similar rig which you can drive and like as it is (and then you just change yours to match).

If your WOT revs are where you want them, try the whale tale second. If your WOT revs are low, change the prop asap so as not to strain the motor. In that case, I'd do the whale last.

[sho305]

Make sure you read some of the tech section on HSR (hydrostream.org) Tons of good setup info on props/setback/etc. I just saw one talking about a hydrodynamics X4(?) 4 blade I think and raving about it, I'll have to check it out. Not sure if it is a bow lifter though, but they said 114mph with one. A 4 blade will help bite on the holeshot a lot and take a few mph off the top. Can also help handling/stability some and is worthwhile if you have these problems, or a good general use prop that is easier to drive.

I have had great luck using the small plane aids and would recommend them. They help a lot without being big and ugly. I used the one for small motors and it worked great. I think the big ones are for real holeshot barges.

I run a Laser II now on my inline. Has tons of bow lift. With the jack you may be able to go with something that has a little less lift. Also make sure the front of your LU has a rounded point and not damaged, the prop perfect and sharp. That makes a difference. Lighten the boat, look for wet foam, etc, bottom clean and so on as it all adds up...even synthetic LU lube.

Don't worry about a LWP, just make sure your water pressure gauge is working good and look at it often when changing setup. I would guess 3-4" deep on the prop would be a good starting point with the jack. On some motors you can fill the top hole or two on the water inlet if you need to. If you can run it higher look into it then; but that 3-4" seems to be the limit to still get bow lift. Sounds like you have a similiar hull to my Checkmate, that is not real light and needs the bow lift to run best. Much different than the hydrostreams for example that can run stern lifting clevors because the bow is so light from hull lift and lack of weight. You also get more lift when you run such high speeds like over 80.

O/B Dude and Double dog have some good ideas for you. Consider searching out a deal on a power jack; then you can lower it for holeshot and pulling, and raise it for top end. You can start with a manual and see what it does, if you get a used one I imagine you can sell it for the same price you bought it for when you upgrade.;) Many use a 4 blade prop for general stuff on these, then a little bigger 3 blade for speed runs.

[mattyc]

Hey guys -- I got a prop from a guy. Paid a C note for it. It's an old Michigan prop SSM 822-c, 14.25 x 22. The guy didn't know much about the prop, so I called Michigan and they said it was an old prop that they didn't have in their database, but that it was equivalent to one of their performance props (don't remember which...)

Well, I got it -- and I'm no prop expert, but just looking at it doesn't get me too excited... First off, it's not a polished stainless steel, so it practically looks like aluminum. Second, the "barrel" (for lack of terminology) doesn't flare out at the end like my other two props -- what is up with that? Third, the blades at least twice as thick as my other props.

Did I get hosed?

ps. I haven't run this prop yet...

[mattyc]

Here's a pic

[mattyc]

here's another

[Doubledog]

If I had that prop, I'd polish the hell out of it :D

Here's the plaining aid Vector Mike did for his rig. Checkered Aluminum cut like an Allison foil.

That has to be the only one I wouldn't be ashamed to put on my boat.

[sho305]

You know what to do...bolt it on and try it!

I had one I tried and it was somewhat like a Laser. Nobody seems to say much about Mi Wheel props here. Make sure the front edge is sharp, and the rear edge is squared off sharp. Should be able to get that $ back out for a SS prop if it don't work anyway. I have seen some props without the diffuser, the flare in back of barrel. They are a little longer there usually. I know the flare helps evacuate the exhaust(and a big one screwed my inline up and made it run rich on that MI Wheel) but it also helps exhaust cavitation on holeshot and handling. Not sure how it affects those two as I have never had a problem there. I do have a Force with the old trim tab exhaust outlet, and the SS prop has a plastic diffuser under the nut??? Don't know why, obviously not for exhaust. I asked about this on a post and nobody answered. Seems that faster props have no diffuser, and little motors/slow boats have big ones. Going to try the Force without it as soon as I find the right size spacer.

The dealer said that this MI Wheel prop had a JohnyRude larger diffuser on it, not a Merc sized one. My Laser has a smaller one than the stock alum Merc prop I have:confused: I know a guy with a inline on a glasstron with a flat extension on his SS prop about 1" long where a diffuser would be.

[mattyc]

When you say the front edge should be sharp -- well, how sharp? Should I be going at this thing with a file trying to put a knife edge on it?!?

[sho305]

Well, nobody agrees there or will tell much, but I do it. I don't worry about cutting paper, and I don't do much close to the barrel. I round it only about 1/8" into the blade and make the point sharp. Most of them come rounded with a tiny flat on the edge, I just keep the round shape and file the flat edge to a point.

I have even filed it to the front or back for a tiny rpm change, but sometimes that did not work so I keep it centered mostly like it was--though I tend to file the back side a little more to give it a hair more bite towards the front(knowing it may go a hair faster and rpm will go up, unless I want rpms higher). I file the round down some, as it will be more blunt than before if you just file the tip sharp, but only back maybe 1/8" or until blade surface is flat again.

Then you can see where they ground the back edge flat and I touch that up so it is a sharp square edge again. That lets the water leave the blade cleanly, much like sharpening strakes or transom bottom on a hull.

Sharpness seems more important the farther away from the barrel as you trim up and the LU nose pushes the water out at wot, the outer half of the blades do the work. More or less I just go over what they did and don't change anything, and I do it in about 15-20 minutes for a SS prop. (You don't take much off carfully filing in that time on SS) I use a course file, and a fine file to finish. I take off very little material so as to not unbalance it, and try to file the same amount on all blades. I smooth any dent or ding best I can. It looks the same when done, just sharper and a little dull for 1/8" at the leading edge. I could polish it back up I suppose.

I also do the Lu leading edge, but I don't make that a point...been told not to or steering can get funny. I round it more 'sleeker' and fix any damage. Like a dolphin's nose. Some props/LUs are pretty good to start with, most of my fishing stuff has not been.;) and had far from sharp edges. SS props are better than alum ones new. Don't expect miracles, but I get 1-2mph, and 4 on one boat. If the stuff is sharp to start with you will get less. If it makes it run farther from the ideal motor power rpm, it will not help either. Lastly, it's free:D

I can get a gain every time if I do that, along with lightening/balancing the boat as much as I can...and all the other stupid stuff.

[sho305]

I did this one but hard to see in the pic. Note the plastic diffuser, with no hub exhaust.

[mattyc]

yeah, it's really hard to see... I spent about 45 minutes shiny-ing up one of the blades on the prop, and it's amazing... This thing had better do what I want it to on the water -- I'm gonna be too attached to it to let it go!!!

[Doubledog]

I'm gonna be too attached to it to let it go!!!

Spoken like a true boater if I ever saw it.:cool:

[sho305]

You can see it has been worked on for 1/8" on the cutting edge. People talk about bead blasting props here and what finish is faster...I figure it is a matter of looks. I'll polish it a little when I get it running better but you have to look close to see it now. That one has a new skeg and paint too. Dig the water intake...wonder how high it will go? Got my plate today:D I'm happy!

Sorry for the wordy post on the prop bit, but that is my take on it. Wanted to make sure nobody goes wild and wrecks a prop. I think I took one careful pass on this SS with a small 4" grinder to start, but I take very little material off. I leave that to a prop guy;) The aluminum props take 10 minutes all by hand. I try to not make the edge any shorter at all. Here is what I mean, I remove the red area at the cutting edge of the blade from the tip to almost the hub webbing where it was factory made pointed: