1988 2.4 175 to 200 front swap help!

[Reaction19]

we swapped the front half from the vertical setup with stock carbs and airbox to a 200 2.4 front half 5 petal setup with 4 petal sportjet cages with ccms reeds,cross drilled intake from the factory from a 225 2.4, and wh20's the carbs had 46's as idle jets and 86's on the mains. motor was idling really rich and bogged and gurgled upon stabbing the gas under a load and smoked tons, so i put a set of 50's on the idle and it got better but its not perfect. i changed the plugs and put a set of br9hs ngk's and that really woke it up. but its rich plugs are dark. i wanted to know what jets i should be running for mains stock compression and timing at 25*! on regular unleaded! thanks in advance!

[tlwjkw]

Stock jets for 20's are 72's except for #2. its a 74. Idle's supposted ta be 50's. It should run just fine with BUHW's also...............Cross drilled (who and how?)"sometimes" makes tunin' a bytch at idle. Make sure ya got a little gap between throttle cam and roller on tha carb. Ya wanna move tha timin' before tha butterfly's move......jmo

[Reaction19]

ok we have some gap maybe 1/8'' on the cam! also its a factory cross drilled intake. i have 50's in it now and its better but still on the rich side. mains are 86's whats a safe tune for it gonna be run at sealevel here in the keys and strung out wide open for long periods of time!

[WATERWINGS]

I think my WH-15's are way rich too with 86's...the last 1/2" or so of petal makes no difference, or even boggs down some, but I'm afraid to go to lean on this ported, exhaused relieved 2.4...but I think thats what it needs...


I'm at .050 or .052 on the idles....MUCH better than when I had .042's or.046's in there....

[Reaction19]

so what do i do lean it or what???

[WATERWINGS]

What I've noticed with idle jets, if its to lean, it won't hadly take off....you can mash the choke in, and it will come alive...

It may also "sneeze" at idle if its to lean....now, the mains....(I'm afraid to go there)

[Reaction19]

I can handle the idle its the mains that have me stumped

[rock]

My guess is a 76 or maybe 78 for a main. On my old 2.4 I ran 80s duirng the spring and fall and 78s in the heat of summer. Motor was stock except compression which wasn't much.
Rock

[Reaction19]

well ran motor today and did a plug chop and #2 is the leanest at pure white looks like it just came out the box followed by 4,5,6 #1 was the best but was a tad too clean for my taste not that light tan color at all! plugs are br9hs brand new! idle cleaned up a bit with the swap to 50's from the 46's but will still load up when idling for more than a minute! guess ill try 52's in the idle! i cant believe this is gonna need more jet! could the float levels be too low??? making it lean! just cant believe a stock 2.4 175 based engine with a 5 petal front and 4 petal cages with wh20's would require such a big main!

[Dave S]

175s have a different tunna than 200s. Did you change that?

[terry taylor]

What is the jet system with these carb ,s . Idle, mid, and high = 3, or do they simply have idle then main jets= 2? Are the idle jets wet or dry= fuel or air? thanks.

[tlwjkw]

Stock jets for 20's are 72's except for #2. its a 74. Idle's supposted ta be 50's. It should run just fine with BUHW's also...............Cross drilled (who and how?)"sometimes" makes tunin' a bytch at idle. Make sure ya got a little gap between throttle cam and roller on tha carb. Ya wanna move tha timin' before tha butterflies move

Put 78's in it and go frrom there. Get rid of tha cross drilled, Put BUHW's in it and if its still givin' a problem with tha way tha plugs read and and don't run for shyt start lookin at tha carbs themselves and/or other parts...........Who knows what its doin' when ya sittin' on tha other side of a computer. We don't know if you are a jamb up mechanic or just a new guy tryin' ta learn. No offense meant. Just something ya gotta consider when your tryin' ta help. Just a hint is puttin' those kinda plugs in it. Tha carb Merc runs just fine and has for 30+ years with tha bu8h/buhw's in 'em. I've turned some of my carb motors way past 8 with buhw's for years....but not for miles n miles!......jmo

[Reaction19]

im not a shady mechanic been racing cars for many years! i can read a plug! plugs arent wet dry and white if i tap the choke it takes off squeezing the ball does nothing! carbs are clean first thing i did when i saw the plugs all white was check for some obstruction in the bowls and jets theyre all clean! i used those plugs because jsre said theyd help with a reading! before this i had always used bu8h or buhw! white plugs equals lean no doubt about it, i know without the cross drilled intake rex had told me it would use 74's and 76's in 2/5 but if i went cross drilled it would take about .10 thousands bigger on the mains!

[WATERWINGS]

What is the jet system with these carb ,s . Idle, mid, and high = 3, or do they simply have idle then main jets= 2? Are the idle jets wet or dry= fuel or air? thanks.

The idle jets are dry......so the bigger you go with size, the more AIR you let in...not fuel.....

[Reaction19]

some ones gotta have an idea!!! idle i dont care about! its the leanness on the topend im worried about! and its stock other than the front half stock compression and timing at 25*

[tlwjkw]

Good information. Just sounds like its more than just a jet size problem. Even with cross drilled it should show rich, maybe not much, but rich on tha plugs with 86's and stock ported 2.4, wh20 motor that is all healthy. I'm computer "calf roped" ............

[WATERWINGS]

[QUOTE=Reaction19;2207745]idle i dont care about! its the leanness on the topend im worried about! QUOTE]

I have never had much luck reading plugs, or piston tops, but I'd rather be to fat than to lean....and thats the way I run now, (even though a couple of piston tops look kinda dry to me).....thats why I'm afraid to go any leaner, even though the last 1/2" of petal is dead or bogs when I give it the last little bit.

[Reaction19]

im gonna put a set of 90's in it and see what it does if it dont get fat then its comi9ng back apart! hopefully rex will come on here and shed some light on the situation

[WATERWINGS]

I have a fairly heavily ported 2.4 200 with exhaust chest hogged out, and I am only running .086's now....EGT's read 1200-1250, but cool down a little when I go total WFO.....I think they read higher when I had .088's in there, so I think I'm still readin' flame....but I'm afraid to go any leaner....(even though that last 1/2" of petal noses over)

[Reaction19]

i also have holes drilled in the front of the cowling leaving the carbs exposed so maybe its gettin lots of air maikn it lean im gonna tape the holes and see if thats it! then ill know why its lean with the 86's in it

[Reaction19]

Also the tuner in this motor is out of a 2.5 280

[WATERWINGS]

i also have holes drilled in the front of the cowling leaving the carbs exposed so maybe its gettin lots of air maikn it lean im gonna tape the holes and see if thats it! then ill know why its lean with the 86's in it

When I first got my Quartershot, the front of the cowl was opened like that, and at a certain RPM, it would surge....once I covered the one big hole, (just under the face plate), the surge went away...

[WATERWINGS]

Also the tuner in this motor is out of a 2.5 280


According to what most people say on here......."Tuner Schmooner"

[Reaction19]

Im gonna run the boat today ill know what the deal is tonight and ill post my results!

[Dave S]

HeeHee Merc put different tunnas in diff HP motors. If it didn't matter why would they bother.

[WATERWINGS]

I know, and agree.....but haven't you heard that alot on here?

[DavidW]

Swapping front halves can cause the crank sealing rings the leak if the front and back don't match up correctly. Don't know how much it would effect the top end but idle would really be a problem. Something to think about if you can't find anything else .

[Reaction19]

i put the 90/92's in it today but got off work late and didnt get a chance to run it today ill go out tomorrow and see whats up i also upped the idles to 52's and she came to life right off idle carbs get all nice and sweaty now and its crispy on the hose! also seemed to pull a little higher when i rap it on thre hose

[WATERWINGS]

Swapping front halves can cause the crank sealing rings the leak if the front and back don't match up correctly. Don't know how much it would effect the top end but idle would really be a problem. Something to think about if you can't find anything else .

Do you pull the dowel pins out when you swap front 1/2's ? (let the bearings line everything up, not the pins)

[WATERWINGS]

i put the 90/92's in it today


Thats prolly gone be real fat.....

[DavidW]

Do you pull the dowel pins out when you swap front 1/2's ? (let the bearings line everything up, not the pins)

Yes I know about the pins . Usually you can get away with swapping front halves but not always. I'm not saying this is his problem only that it could be if he keeps getting uneven plug readings and there are no other problems. I have seen it not work with my own two eyes and been told there can be problems by others who have alot more experience with this than me. I don't claim to know it all, I'm just throwing ideas out there.

[Reaction19]

yes dowels were removed and everything was replaced even used new cork strips and sealed the front half to the block then torques everything to specs! nothing seems wrong other than it wants fuel! poke the choke and it starts to scream big time pulls like a freight train! gonna make it rich hopefully with the 90/92 combo then lean it down little by little. definitely has tons more torque down low.

[terry taylor]

Does the factory use cork strips on assembly thanks?

[fyremanbil]

I may be the only one who thinks so, but those jets don't sound too large. My 2.4 fishing motor, basically stock w/28cc heads and cross drilled manifold wanted 92's to get the EGTs down to 1250, pistons were still mostly dry. This was for an enduro race with 3 mi straights. It's about right on when you consider the Merc ModVP 2.4 oval port engines used 93.7's for jets.

[Reaction19]

runs like **** still im taking carbs off and putting my good set of wh39's i had in my ported and cross drilled 5 petal 2.4. has 80/82's and would pull way past 7500! so i know theyre good and will run! i just have a feeling theres something wrong with these wh20's !

[tlwjkw]

i just have a feeling theres something wrong with these wh20's !

Got a set JUST LIKE 'EM. They wore us out for about a week......................Never did find out what was up with 'em. They just would not run right no mater what ya did to 'em! Guess thats why they came from tha "for sale" section!!!!

[Reaction19]

I ran the boat today with the wh39's and it's better idles good and pulls good but still gotta poke the choke for it to turn past 5500! What gives could the fuel pump not be keeping up idk what else to do! These carbs came from my old motor so I know they're good! Definitely an improvement but not perfect! When it was stock it would turn the same prop 6200 now it won't inputting that's changed is fronthalf reeds and carbs! Also could the br9hs plugs be the problem???

[Shaun Torrente]

DO you have an electric pump or just the stock pulse pump... I would have at least a holley red on it.

Shaun

[tlwjkw]

Didn't ya change tha fuel pump when ya went from vert. ta horz front? We've never tried those plugs. Donno? Like said at tha very start. Tha 20's with stock jetting and basically stock motor should run a hole in tha wind just like tha bunches that are still out there runnin' ta day. Thats why we jacked with tha 20's we had for so long. But ours turned out ta be tha carbs. Yours sounds like might be a different problem.............

[Reaction19]

Stock 225 carb fuelpump! Old five bolt style that's it 3/8's line no anti siphon in tank and tank has 1/2" pickup!!! I'm gonna install a Holley red to see what's up!

[tlwjkw]

What did the five petal front half come from?

[Reaction19]

2.4 200

[tlwjkw]

Does the factory use cork strips on assembly thanks?

Somewhere in tha later years, maybe when tha production motor went to o-ring heads not sure, they STOPPED usein' 'em...........

[Reaction19]

I'm gonna put new fuel line a lectric pump get rid of primer bulb and grey fuel line and also change the online merc 3/8's fuel filter also gonna take out fitting on tank and reseal it there also! I'm doing that this morning the going to run the boat so I'll post results this afternoon!

[6Killer]

What mains came in the 39's and what are you trying to run now?

[tlwjkw]

Where ya been 6 ? Has someone put a muzzle on Rex? Figured he'd be on this one.......And yeah, Bobby is in church anytime tha doors are open. Guess I'm tha dark side on tha duo.....

[6Killer]

Where ya been 6 ? Has someone put a muzzle on Rex? Figured he'd be on this one.......And yeah, Bobby is in church anytime tha doors are open. Guess I'm tha dark side on tha duo.....

Just got back myself.

Talked to Rexy the other day. I sure wish he lived closer.

Six

[Reaction19]

Ran it today with a mr. Gasket pump as a pusher and a fresh set of bu8h and new fuelline it's better but still needs choke pushed to scream if not rpm's vary 5500-6000 up and down

[Reaction19]

Also I've pmd Rex a bunch of times with no response hope he alright!

[Reaction19]

Wondering if stator is the culprit or coils!

[DavidW]

Not if choking it clears it up

[Reaction19]

one pkoe of the choke every few seconds make it roll out!

[DavidW]

Did you remove the stock pump when you added the electric? Sure sounds like a restriction or blockage somewhere. Definitely a fuel problem Also keep in mind a vacume leak from intake manifold or leaking crankase can act like this too.

[DavidW]

Try larger jets in the wh39's?

[Reaction19]

Plugs don't look lean! Actually a little fat! I didn't remove the stock pump! I'm gonna though block it off and just mount my holler with a regulator instead and just do away with all that! I've checked for vacuum leaks with carb cleaner around all the front half carbs and reed plate nothing! All seems sealed

[Reaction19]

i took out the stock pump and installed the holley with regulator so ill know hopefully tomorrow if that was the problem. god i cant wait to be able to really string it out! motor feels strong just gotta work the bugs out!

[WATERWINGS]

I run my Holley directly from the regulator to the carbs.

[Reaction19]

Thats what in doing now so hopefully that cures this thing!

[6Killer]

How bout a blockage behind one of the seat assembly's. What mains are you trying to run?

[WATERWINGS]

Although I have run the Holley to the Merc pump also without any problems.....?

[Reaction19]

It currently has wh39's with 82/80's 82 being in 2 and 5!

[6Killer]

Go to 86/88's, if your symptoms persist, your problem is elsewhere.

[Reaction19]

But plugs look good and these carbs were on my other 2.4 with high compression and exhaust chest work and was fine at 7500 rpm.

[6Killer]

But plugs look good and these carbs were on my other 2.4 with high compression and exhaust chest work and was fine at 7500 rpm.

With which front half, reed cages and intake? What jets?

[6Killer]

A stock 2.4 200 with compression, reed cages, cross drilled manifold and tuner runs on 86/88 mains for extended hs running.

[Reaction19]

a stock 2.4 200 with compression, reed cages, cross drilled manifold and tuner runs on 86/88 mains for extended hs running.

i ahve all that but with stock compression

[Reaction19]

Ran boat today falls on it's face at 6k plugs look fine accelerates good but struggles with high rpm! Could it be the stator??? How do I check? Trigger? Coils? It can't be carbs or fuel has a Holley blue with a regulator and is at 6psi!!!

[Reaction19]

I found four weak coils and a weak stator so I changes all six coils and the stator also the rectifier! Motor idles much better and accelerates day and night difference! So I put it in the water and went for a ride! Gets to 5500 and now I gotta poke the choke again to get it to spin up plugs were a lil lean so I'm gonna fatten her up and hopefully it will be golden!

[Reaction19]

i put 82/84's and its better but i was thinking i drilled some big holes in the factory fishing cowling in front of the carbs these cowlings get air from the back of the cowling could it be that its getting air from the back and now with the front holes its disturbing the air and actually hurting the performance maybe sucking the air out of the carbs????

[terry taylor]

i put 82/84's and its better but i was thinking i drilled some big holes in the factory fishing cowling in front of the carbs these cowlings get air from the back of the cowling could it be that its getting air from the back and now with the front holes its disturbing the air and actually hurting the performance maybe sucking the air out of the carbs????

The answer is no. I shouldn,t say this, but , oh I won,t say it thanks.

[DavidW]

Go to 86/88's, if your symptoms persist, your problem is elsewhere.

Put some duct tape over the holes and you will know for sure....and after that try what 6Killer suggests. It's not so good to keep running it if it is somehow too lean
and if poking the choke clears it up it has to be.

[6Killer]

Carb motors don't like to be force fed air.

[Reaction19]

6 killer maybe thats the problem im getting a set of 86/88's to try also and i have a stock cowling im gonna try the cowling tonight first then if it gets better ill change the jets if it needs it! ill keep u posted and to all that have helped thanks its very much appreciated.

[Reaction19]

Ran boat with another cowling no better actually ran better with no cowling! Carbs get really milky/snotty!!! Did manage to turn it 6100 but it's very sluggish and bogs when going 3800 then just letting her eat has a little stumble! Idk what else to do could the crossfrilled intake be the culprit??? I'll do anything at this point!

[fyremanbil]

Milky stuff is water/oil, either from water inducted into the cowl or condensation on the carbs. I've had lots of factory cross drilled manifolds that worked fine. Does it still run better with the enricher on? If so, give it the fuel it wants by increasing jet size and see what it does.

[Reaction19]

it does pick up rpm noticible in the seat of the pants and also by watching the tach it does rise when i poke the choke! if i hold the choke in though it falls on its face! motor currently has 82/84's in it! and also has a 280 tuner but the tuner has no effect on the poke the choke thing. also when cruising at like 3800-4000 and i romp it it has a stumble sometimes not always but sometimes. could timing be an issue we had it set at 25* before we swapped the front halves but we havent checked it since! i just want it to run right. also its really bad on the fuel consumption now worse than it ever has been!

[terry taylor]

Timing not an issue thanks.

[Reaction19]

Quick follow up we found the problem or should i say chris carson of chris carsons marine found the problem. Great guys to work with never charged me a penny and was always there to help me out throughout the entire build/ problem. I have his reeds and with his advice the boats been faster than ever. And also better on fuel than before. Once again theyve impressed me. So much that were already planning a 2.4 hotrod motor coming soon. Thanks chris and all the guys there sam,stan,josh,are great guys always looking to help and lend a hand.

[WATERWINGS]

what was the main fix?

[Reaction19]

Took the 280 tuner out and put in a bobs.

[JWTjr.]

Took the 280 tuner out and put in a bobs.

I'm guessing the 280 pipe was out of a 20" engine?

Tiger

[Reaction19]

I have no clue!

[WATERWINGS]

Took the 280 tuner out and put in a bobs.

The TUNER was what was killing the power?.....A 280 tuner?....hmmm ?

[JWTjr.]

the 20" 280 pipe is much longer and with a different progressive taper than the 2.4/Bob's style pipes. It will sit lower in the water when at idle (depending on the boat the engine is mounted to, of course) and therefore have different idle and off-idle performance characteristics (for example, loading up, stalling, etc.) because it's deeper in the water. At the top, it can limit rpm due again to it's length. Midrange should be strong with that pipe, though.

John

[terry taylor]

Does that type tuner not have some way to relieve at idle. Omc cross flows have the longest tuners and seem to not interfere with performance thanks.

[6Killer]

You got suckered into trading your 280 tuner for a bob's. Didn't you!

A tuner is not going to cause your motor to want you to lay on the choke to run.

Have you been to the water? What does the motor turn now?

Inquiring minds want to know.

[Reaction19]

I still have the 280 tuner! Didnt get suckered into anything i changed the tuner without touching anything else and it came to life! Also had to jet it down because the plugs were black as can be!

[6Killer]

Glad to see that someone didn't take advantage of you on the tuner thing.

The 280 tuner ran on the 175 without issue. It will run on the new motor also without issue.

You have inadvertantly fixed your problem. The tuner is not it!

How about some performace and jetting figures.

[Reaction19]

How can that be when all i changed was the tuner and it runs fine now!!! Had to be the tuner from one day to the next it didnt fix itself!!! After i got it running plugs were black before i changed the tuner we had gone all the way to 90/92's on the jetting and it was still white and lean soon as i changed it was black and wet! If youd like some jetting help call ccms as they did all the work to my motor great guys to deal with always eager to help!

[tlwjkw]

If youd like some jetting help call ccms as they did all the work to my motor great guys to deal with always eager to help!

There ya go Chris. You can go ahead n through Mikes number away too :reddevil: Not that ya really needed it!

I bid 50 bucks on tha pos, trouble causin' tuner. Just ta get it outta your way :thumbsup:

[6Killer]

So who has been doing the work from the getgo..... CCM or you?

Thanks for the advise, I think I can handle my own tuning.........Maybe

[Reaction19]

ccms lent me there shop and there knowledge i wanted to be part of the swap as any of us would want chris told me not to use the tuner from the get go but hey a 280 tuner has to work right!!!!! lets just say i should have listened! and about the tuning you asked!!!!!

[6Killer]

You still haven't let us know your present performance.

[terry taylor]

Tuners those silent killers, and mystry pieces of pipe yike They are to long, to short, to round,to sqare, to bell shaped or just plain secretive thanks

[Reaction19]

6 killer boat picked up 500 rpms with the same prop height combo! This is after we sorted out the problems we were having and thats with a 5 petal front 4 petal rubber cages with ccms reeds and wh20's!!! Boat runs awesome now im gonna start raising the engine and playing with props!

[Reaction19]

By the way im not saying that tuner is a complete pos im saying on this setup it was the problem on a 280 they sure work, but on this lil ole 2.4 175/200 it didnt like it!

[6Killer]

So...........you are saying the tuner was the reason you had to lay on the choke?

[kingsbiship]

Something doesn't add up!

[tlwjkw]

Something doesn't add up!

Tha tuner?

Not even on a Chinese calculator!!!!

[TEXAS20225]

Tommy lets get Raceman to analyze the tuner pros and cons for us!!!!!! Norris where are you when we need help

[ChrisCarsonMarine]

" better to remain silent and be thought a fool,than to speak up and remove all doubt"
My ideas on this situation are as follows...first,Reaction didn't mention the 280 tuner was added at the same time as the front half swap,against my recommendations,I guessed it would be toooo long and belled for a 2.4 at 6500-7000 rpm,about the most rpm you could hope for with a stock port/compression 2.4.The can was removed at the same time also,and I feel the tuner and lack of adequate back pressure resulted in a lot of fuel/air passing through the motor instead of stopping in the cylinder as it should if the exhaust was TUNED correctly( isn't that what a tuner is for?)It would seem this could account for the top end lean condition,resulting lack of top end,accelerating with the primer,sucking fuel like an ocean liner,and barely responding to main jet changes.I don't proclaim to have all the answers,and am happy to learn new things everyday...in this case the replacement of the very long belled 280 tuner with a more conventional Bob's seems to have solved the problem,Chris

[rock]

Seven pages ago we were discussing jets. Where did you finally land
Rock

[ChrisCarsonMarine]

Rock,as to the jets,I'm mot sure ,I think the mains are 84/86 in 20's,probably a little rich,Reaction can confirm or correct,I know that once the tuner was replaced the bigger jets that still needed the primer to nudge toward top end were soggy rich,chris

[Reaction19]

Chris you are correct 84/86 in the 20's and 50's on the idles runs like a raped ape!!!

[rock]

If you have the jets give a smaller one a try. You might be pleasently surprised.
Rock

[Reaction19]

Yeah im gonna try next size down but dont wanna get it to close to the edge!

[Erine]

You didnt happen to measure the Bobs tuner did you. Im having similar issues on a 7 pettal 2.4. Was told by a freind when he used to race 2.4s they would mil the exaust adapter and cut and bell the tuner to make it as short as possible. I have several tuners that have been cut ranging from 3 inches to 6 on the long side. Was curious on the length of the bobs tuner. Thanks Ernie

[terry taylor]

" better to remain silent and be thought a fool,than to speak up and remove all doubt"
My ideas on this situation are as follows...first,Reaction didn't mention the 280 tuner was added at the same time as the front half swap,against my recommendations,I guessed it would be too long and belled for a 2.4 at 6500-7000 rpm,about the most rpm you could hope for with a stock port/compression 2.4.The can was removed at the same time also,and I feel the tuner and lack of adequate back pressure resulted in a lot of fuel/air passing through the motor instead of stopping in the cylinder as it should if the exhaust was TUNED correctly( isn't that what a tuner is for?)It would seem this could account for the top end lean condition,resulting lack of top end,accelerating with the primer,sucking fuel like an ocean liner,and barely responding to main jet changes.I don't proclaim to have all the answers,and am happy to learn new things everyday...in this case the replacement of the very long belled 280 tuner with a more conventional Bob's seems to If the tuner was discussed have solved the problem,Chris If the tuner is so critical why did he put himself through all this hassle .Myself I don,t agree with any back pressure theory, back pressure is evil for any outboard. The ports determine fuel timing and the tuner is just an exhaust pipe, pulse tuning helps, but that is not evil back pressure thanks.

[Dave S]

HeeHee Tunna wars......When ya change tunnas and carbs and fronts........Merc has Jet charts for diff set ups. Must be THEM......

[TEXAS20225]

i heard the tuner theory many times in the last 20 years and bought into it in i guess its was 1995 with a Gfarce tuner you know the one that give you a bunch more horse power or was that horse pooky here is a link on tuners by one of Scream and Fly's own and some good comments by Raceman this post is 10 years old so its not a new topic i agree there are some totally wrong applications but Joe boater aint gonna know too much about what he is really getting http://www.screamandfly.com/showthread.php?7717-Ex-Tuners&highlight=tuners

[Dave S]

Hee Hee Then Merc wants to waste time casting Tunnas And 7 Peddle fronts....Huh...Must be a learning curve for them.....

[donmac]

if the tuner didn't matter the manufacturers wouldn't have spent millions putting them in!

[terry taylor]

if the tuner didn't matter the manufacturers wouldn't have spent millions putting them in! The tuner does matter it,s an exhaust pipe .. Would you run your car with the exhaust emptying from the cylinder head port thanks?

[donmac]

The tuner does matter it,s an exhaust pipe .. Would you run your car with the exhaust emptying from the cylinder head port thanks?just like john force!

[terry taylor]

Force has 8 pipes,no tuners no back pressure thanks

[Reaction19]

this is getting out of hand in this particular application the tuner was the only thing that changed from oneday to the next and the issue went away simple as that believe it or not!!!! we tried different carbs wh39's and wh20's and went all the way from 80/82's to 90/92's changed stator and all six coils and wires and changed the plugs 3 times during the course of this matter in trying to figure out the problem, i myself did all the testing and was to the point of putting my original 2.4 200 powerhead on the boat and just giving up on this, when chris came to me and said what about the tuner, so i said what do we have to lose and we changed it, the next day we went to the water and presto poke the choke and it falls on its face the plugs got black, and the motor gained acceleration and topend speed and rpm. we even used the same powerhead gaskets! started to lean her down and she runs great! i believe that the tuner in this particular application and rpm range and setup was the problem hands down... im not saying that it wont work on a 2.5 225 promax cut to 260 specs with 150psi compression, but on this 5 petal front 2.4 with wh20's it doesnt work for me, i couldnt get it to perform! also mariner racing is having the same problem with his 2.4 and he is also got a 280 tuner in it! so you be the judge goes to show what works for one doesnt for another!

[terry taylor]

I don,t refute that, but I refute tuner infatuation as being more than what they are, or expectations by some from a piece of piping , cast alloy exhaust pipe thanks

[Shaun Torrente]

I am not smart enough to tell you why "scientifically" tuners matter but they do!! Our team spent a full day running through about 13 different tuners on the F1 boat... We have a good data aquisition system, and it made as much as a .3 second difference on a 9 second acceleration... That does not sound like much but it actually alot... .3 tenths is a boat length at 100 mph... We have also broke tuners during the race and then had a restart and the boat does not accelerate without a tuner... So i have to disagree with the no backpressure theory, it is just that a theory that does not work in the real world.... Our engine builders have also spent A TON of time in the exhaust chest to make power

Not to mention the Hydro Tec tuners that I did a bunch of testing on for Wayne... It makes HP and MPH on every setup I have ever put it on... Tuners do work and effect performance sometimes negatively

Shaun

[6Killer]

. Tuners do work and effect performance, sometimes negatively

Correct, but a tuner is not going to cause you to have to lay on the choke.

lol...Three tenths, to the average boater it means nothing. To a racer, it makes us giddy!

[Reaction19]

well come to the keys pay for my gaskets and ill put the tuner back in and you can have at it. i dont know what else to tell you!

[kingsbiship]

I'm not buying into that prognosis either! I won't believe a tuner can alter an engine to the extent that
it needs a choke or other means of enrichment to run correctly! C'mon!!!

[ChrisCarsonMarine]

Tuner Test,101.for 2.0,2.4,and 2.5 mercury outboards.
1.test run,record results
2.trailer boat,tilt motor
3.remove cowling and gearcase
4.remove 3 rear down facing bolts,adapter to can...remove nuts 2each side from long Powerhead studs
5.carefully remove retaining ring from bottom of swivel tube,can (exhaust housing)will now slip off
leaving Powerhead supported and held by upper mounts,and exposing tuner.
6.remove and replace tuner,choose a nice one,
7.reinstall can,nuts,bolts,lower unit in ...1 1/2 hours working alone with hand tools,or,our preference,45 minutes,start to finish with a helper.
8.test run,record,compare results.
Note,nothing changed,removed,unrigged,or altered regarding the Powerhead,the only reason for removing the cowling is to gain access to the three adapter to can bolts.Not much opportunity to inadvertently fix the real problem along with the meaningless tuner change,Chris

[DavidW]

I suppose I probably don't know anything but I will say I'm a little curoious as to what would have happened if he would have got large enough main jets in there to have not needed the choke to go, But I also understand the motor seemed too rich at anything below full throttle so it is just a thought.

Another thing I was thinking is that on most two strokes besides outboards any little pipe change makes a huge differance as to what rpms peak power is made and how it has to be jetted. Just think of the differant pipe kits for quads or other similar engines that come with the proper jets or at least recomendations. I also know that on some smaller motors the porting is differant depending on whether you use a muffler or a pipe. Maybe a 280 has a lot differant exhaust port timing or configuration to make use of that tuner. As I said these are just thoughts from someone who probably knows nothing...

[ChrisCarsonMarine]

David,you know more than you let on...

[Reaction19]

Agreed!!!

[DavidW]

David,you know more than you let on...

Unfortunately, I have found that to be the path of the least resistance.

[DavidW]

Glad to hear you got the motor running like you wanted Virgil.

[Reaction19]

Thanks david now just gotta have time to try all these props im aquiring!

[DavidW]

That's the fun part! I know Beef and his brother did best with a chopper 2 and a eagle et. My boat has been best with choppers. I do want to try my seebold modified yamaha drag 28 again now that I have been driving the boat a while. It doesn't have enough bow lift for carrying two people but maybe me by myself?? My boat always has a 26 big ear chopper on it , seems best all around carrying the wife and kids with me. It's hard to get out on the water much without taking them all with. They love the boat!

[Reaction19]

I know what u mean my two little ones and the wife are always with me too. Ive run the best so far with my 32 clever! But now have a hydromotive 27, 24 bigear chopper, and a 14 1/2x30 clever to try and im ordereing a 28 offshore cut from ds77 this week. I wanted the 24 chopper for all around riding but may be too small we will see.

[Dave S]

The end of tunna wars......Na.....

[terry taylor]

The end of tunna wars......Na..... You have good eyes thanks,