951xp jetboat wont rev past 3000

[Izzy 951]

This is my second post, update I bought new mpem and loom got it running idols smooth as but as soon as I rev it, it starts to break up like it's missing (around 3000) and I get quite a bit of white smoke out the exhaust.

The loom I bought came off a ski same year etc, it doesn't have the charging wires from the magneto. Just wondering if there something stopping it from reving out electronically or its something else.. battery was charged but I'm gonna try a different one just in case.

Trying to avoid taking it back to the shop took a month just to get a spot to get it looked at.

 

[DeWet]

My GTX DI did kinda the same and it ended up to be a faulty fuel injector so was running on 1 cylinder.
Try checking if both are running by checking each by unpluging fuel injector connector or spark plug.

 

[Izzy 951]

It's carburetored so I did that with the plugs front cylinder ran while I had the back cylinder plug off on the block, it idled and the plug that was on the block had a decent spark..

 

[Izzy 951]

Anyone got more ideas I'm gonna do some more work on it this weekend.

Thanks in advance

 

[Izzy 951]

It's a carburetored 951 in a 3m jetboat, it went like he'll when I first got it, the only thing I've changed is the faulty Mpem and just creature comforts for a jet boat steering, seats, accelerator pedal etc.

Do the carbs get clogged quite easy, the boat did get some sanding done so some alloy dust could of found its way into the carbs...

 

[rusty nail]

if the new mpem is from a 951 jetboat(ie challenger, sportster, etc). and not an xp, then the boats have a neutral safety switch that will not throttle up in neutral.

 

[rusty nail]

Quick test if your fuel system is to do this. Hook up alternate fuel source(bypass your tank, fuel selector, fuel filter, etc) go directly to the carb and fire it up. If it still does not throttle up there is a tiny cartridge filter inside the carb. Locate it and see if it is clogged. You can then at least rule out fuel issues

 

[Sandman251]

Might help if you could say exactly what year, make and model jet boat you have. Don't know if we're dealing with a language barrier here, or not. Is it a jet ski or a boat? If you're saying it is 3 m it is definitely not a boat

 

[rusty nail]

I was guessing he has a 3m aluminum hull jet boat with a 951 carbed seadoo motor in it. In the first post he mentions he purchased a replacement mpem for it and maybe he got it from a seadoo boat instead of an xp, which if the case there may be a neutral switch required where i believe the xp does not.

 

[L. Dean Ficarro]

Well, im wondering if he got it. If not, more information on what you have and what you are using would help. Donor engine, clean fuel lines, carb jetting and settings good, butterfly set properly, stock box on intake

Help us to help you!

 

[POPPS]

What is an 951XP jet boat?..just need clarification,,,is this a single 951 carbureted motor?

 

[rusty nail]

he said 3m jetboat in his first post.....so this photo is what i am guessing. he has a 951 carb xp power plant in there......guessing. He mentioned that he replaced the mpem so i said there is a possiblity he put a 951 mpem from a seadoo jetboat. i think some of the old sporsters or challengers maybe had a single 951? thats a guess. if that is the case there is probably a neutral switch he need to address....again....guessing. Sorry if i was the culprit for some of the confusion.

 

[POPPS]

If it is missing charging wires it will not rev out.

 

[fatblockabody]

I don't think this is it in your case but I just had a delaminated exhaust hose creating a rev issue around the same RPM in a ski. Would be worth checking for soft spots for all the longer it takes to check.

 

[POPPS]

apologies,,,this thread is a bit difficult to follow,,,if any DI,,(electric fuel pump),,,or jet boat,,,is not charging,(bad rectifier, or stator),,.,or has a weak battery,,.it will start but not rev out..,,just my 2 cents,,,

 

[rusty nail]

on may 6 he said it is carburated.