3.0L wont Rev over 5100rpm

[Tranzman]

Has anyone had experience with a 225/250hp 3.0L not reving over 5100rpm. I tried boat only with a 23 pitch prop and on GPS 55mph, 7 people in boat 54.6mph, Towing one skier on a dragski with two people in boat managed 58mph, This motor used to rev to 6050rpm with a 30ET lightning on a lighter boat. Im sure it used to rev higher when I first put it on this heavier boat. Could this be a reed issue or too heavier boat? I dont have any lights or horns flashing and when i give full throttle the Exhaust temp drops from 1250F to 1100F.
One thing I changed was to 300pm Carbon Reeds and Brucato Reed intake, It always has run an SVS on both boats which definitly gave it more HP. I also run 300pm heads 67cc bringing up compression to 125psi.

[150aintenuff]

check to see if a plug fouled or if a wire fell off... those are the easiest things that would cause an RPM loss... seems like its acting like its missing on a cyl...

[HighVelocity]

I would go back and look at the reeds. Maybe try the old ones to see if you get rpm range back. It sonds like you only changed a few pieces of the puzzle. It shouldn't be to hard to figure it out.
Good Luck
Ed

[Tranzman]

Last week I changed all the reeds intake and took off the SVS - everything back to standard, put the 23 pitch prop back on and tested it. Only 5100rpm again, But now my EGT drops to 990F. Really no change. So I rechecked TPS and somehow WOT had moved to 4.05 volts, This was interesting as the idle setting was .95 as per factory. I wound my foot throttle stop back so WOT read 3.1 volts and now the boat pulls hard through to the RPM limiter 6050. EGT reads 1200F at WOT(wide open throttle) but under load at low throttle gets up to 1500F. Does anyone know what standard 3.0L EGT's should be? I know that 1500F isn't the most promising number but it does go good.

[HighVelocity]

Did you reset your rev limiter. My 3.0 limit is 5750rpm. I would like mine to rev that high.


So, it sounds like you had bad TPS setting? Could that have moved when you put the reeds and intake on?

[hydroslide]

My '97 3.0 225 EFI did the same exact thing. It use to rev 5700, then the next time out wouldn't rev past 5000-5100. I did compression tests, leakdown, pulse and electric pump tests, reset TPS. Everything was fine. I'm getting ready to pull off the induction system, thats the only thing it can be. A clogged injector, or the screen in front of the injector. Pull off you fuel filter/seperator and empty it into a glass and see if there is any junk in the gas.

[Tranzman]

Did you reset your rev limiter. My 3.0 limit is 5750rpm. I would like mine to rev that high.


So, it sounds like you had bad TPS setting? Could that have moved when you put the reeds and intake on?

High Velocity, I have a 1995-96 ECU, This year the rpm limiter was set at 6050. In 1997+ they changed it to 5750 so the 250hp & 300hp motors looked better. What year is yours? My mates get pissed when they have to run taller props to keep the same top end as me. The TPS was definitly not moved as it is bolted to the injector body. I should have checked it at WOT 1st. I knew what it should have been. Have you tried a Brucato SVS?

[Tranzman]

My '97 3.0 225 EFI did the same exact thing. It use to rev 5700, then the next time out wouldn't rev past 5000-5100. I did compression tests, leakdown, pulse and electric pump tests, reset TPS. Everything was fine. I'm getting ready to pull off the induction system, thats the only thing it can be. A clogged injector, or the screen in front of the injector. Pull off you fuel filter/seperator and empty it into a glass and see if there is any junk in the gas.

I had checked the fuel filter already and run another filter in the boat with a surge tank, I had bypassed that to eliminate that already. Does you setup have EGT pyro's? If it does watch what happens with the EGT temp when it stops reving past 5100rpm. What was the last thing you touched on this before it stopped reving? Your problem could be different than mine but let me know what the WOT TPS setting is.

[HighVelocity]

Mine is a 2003 225 EFI. I recently hit 71.7mph with a 24 trophy plus.:) I think could get a few more mph if I could rev it some more.

[Tranzman]

High Velocity, your motor will have the late type plenium chamber so the SVS wont fit and so far no news on adjustable rpm limits, try a higher pitch prop! how many hours has your motor done?

[HighVelocity]

This motor is a factory reman, new in 2003. The motor was never put on a boat though. I'm guessing it only has about 20 hours on it.
I babied it for a few weekends but lately I've been drop-in the hammer.

[Tranzman]

High Velocity, Is your EFI system a two computer set up or one computer on the side of the motor? These 3.0L motors dont come on song till they've done over 50 hours so just keep thrashing it and you'll know when it starts freeing up, Get a GPS and moniter the speeds of different props so you know where your at. Do you tow skiers over there? What sort of boat is it on?

[HighVelocity]

The hull is a 22 Ft velocity from velocity. I have a one comuputer motor on the side of the motor. I think something has changed, I went from 64 mph to 72mph on GPS. I thought it was a prop change. I went from a 24P generic stainless to a trophy-plus 24P. Maybe something clicked over in the computer too. I only heard the rev limiter go off once with this prop. I hit a wave and skiped over the next 3, that was hairy.

As for skiing, I do some up the Mullica River with my brothers boat. His boat is made for that stuff.

Were are you at with your boat?

Ed

[Tranzman]

I have to do some more testing but at this stage with the intake all back to standard it's going OK. So far with a 26ET lightning it does 74MPH @ 5800, I will try some other props. I had it doing 80mph previously when the SVS was hooked up using a 29'SRX. This boat is a 21ft Bullet (austrailian design). What does a velocity look like?

[amityray]

What does a velocity look like?

Here's one.

[HighVelocity]

I'm not sure about how to attach pics to this forum. I can send one to your address.