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02 XP RPM too low

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Rdspins

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I have a 2002 Seadoo XP with what I believe was called the RIVA stage one kit on it. Problem is the last couple of years it is hitting 6k RPM like a rev limiter... Which of course is limiting its speed, have taken it into many shops and even had the engine replaced. Rebuilt jet pump, yet still not any better. Hole shot is fantastic and accelerates starts and runs great. The only time it will go over 6k is when you spin out (no load) but as soon as it sinks into the water right back to 6k like a rev limiter. Any Ideas?
 
1. compression
2. fuel delivery
grey fuel lines?
carbs clean?
correct jets?
good fresh fuel?
correct oil?
3. air - air box good
4. spark - plugs new? gapped? wiring good?
5 TPS - on throttle cable, under the oil tank. - FSM will tell you the volts.
6. prop - good shape? replaced? driveshaft - carrier bearing?
7. RAVE valves clean? hoses without leaks?
8. RAVE valve relay good?
9. water regulator good?

have fun :) that ski should hit 7k WOT in the water if it's 100% or close enough to not care. I could rebuild that ski in my sleep.
 
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SabrTooth thanks for the quick reply unfortunately I ended up going on a 3 day trip for work that lasted a month and a half. I have previously checked 1-4 with everything checking good. Note i no longer have the stock air box or tuning pipe with this upgrade kit. However it all worked fine previous to these issues.

5. I am not sure what you are talking about on the TPS, i do have a multi meter so i can check whatever volts i need to. I also heard the the rectifier it the mpem can go bad but I also cant find the pins to check that.

6. I am leaning toward maybe the prop is bad. It looks fine but again it hits the rpm like a rev limiter but when you spin out or its out of the water the machine will hit 7k no problem. Drive shaft looks good and carrier (trust?) bearing was replaced.

7. Rave valves are clean. visual inspection of hoses look good. might have to do a soapy water test with it running.

8. Rave valve relay? - no idea what or where this is.

9. Water regulator.... no idea what to even check here either - if on the same note there is also a micro touch box that the wires go to a device that is connected to the hoses that go to the tuning pipe... unfortunately don't know that that does either.

All this was put on when the ski was new back 02-04 time frame i believe and was a kit so now I don't have much of an idea of what all it does.
 
The problem you're going to run into, may be mix matched parts. The 951 is already one of the most tweaked engines from the factory, with an expected life of 200-300 hours. (10 years).

With a 100% factory setup, I can tell you how things should go, but I'm going to sound like a dealer and say... return it to stock...

But, in the mean time, I'd check your air/fuel mix, by googling, and learning to read spark plugs. That should go a long way.

#1 is compression - without that you have nothing. a 951 should read 110-130 new, the important part is that both cylinders read the same. not the actual number... (long as it's not like 10!)

The TPS - Throttle Position Sensor is under the oil tank. it sends 5v to the MPEM (I think) below 80% throttle, and 0v above that (possibly the other way, it's been a few years).

the RAVEs are the black round things held on by 2 6mm (maybe 5mm) bolts on each piston, they change the exhaust valve height, they open to give you more top end. there is a hose that goes from under the engine (above the starter I think) that goes to a 12v solenoid just above the water out on top of the engine. there should be a grey 90 elbow there. Verify all the hoses are good, not leaking, and not clogged. also applying 12v to the solenoid should give a solid CLICK noise.

in the back of the ski, on the 'muffler' (water box) there is another RAVE valve that likes to leak, this one restricts water at higher RPMs to give you more power. verify it's operation... usually remove it, see how it works, and blow into one end, while moving up/down. should open/close with exhaust pressure.

if the prop was bad- usually has the opposite effect - pushing less water = less load on the engine, allowing it to spin up with little movement.

Without the stock airbox, you've raised the air pressure into the system, with the engine not having to work as hard, the carbs would have to be adjusted. Basically the opposite of a choke.

If you hit 6k WOT, pull the choke just a little bit, see if your RPM goes up or down. With the restricted airflow, it should be forced to pull a bit more fuel. If that works, it means you're running lean, and don't have enough fuel to hit full power.

7k is a 'best case scenario'... ideally aim for 6800... and call it a day.
 
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