Seadoo XP 99LTD surging problem

[pazzo]

Hi Guys,

I have a 99XP Ltd and having an issue with it.

What it does, after an hour or two on the water, it started to choke up, and flat throttle does not go over 3000rpm-4000rpm
Once we take it out the water and free rev it, seems ok.

Take the ski out of the water, next day it is fine for another hour then it does the same thing.

I have taken it to the local seadoo dealer and had a full service and also had the carbys rebuilt.
Plugs seem ok, i have bought it back to seadoo to check the carby settings out again.

Has anyone heard of this happening? something else i can check?
I have heard of the Raves playing up? could that cause this?

Thanks for your time,

Sam

 

[Dr Honda]

From what you said... I would think that it's overheating, or your rave valves are gummed up, and are in need of a cleaning.



As an FYI...

Never rev up the engine out of the water. First... Without a load... it will always rev up. (so that won't tell you anything anyway) Second... these engines are known to "Run away" without a load. There are reports where the engine will rev WAY past the limiter, and the only way to kill it, is to cut the fuel supply, or pull the choke if you still have it. (pulling the spark plug wires won't kill it) Finally, by the time you get it shut down... the engine will be over heated, and could have damage. So be careful.

 

[pazzo]

Thanks for the reply Tony.

I am no expert, but i don't think its overheating. I initially thought that at first, but let the ski sit for a couple hours in the water to cool down, but as soon as i started it up, it was still running like crap.

Usually as soon as it starts running bad i put it on the trailer and it goes back to seadoo, but the last time i was out, i had a good 3-4min ride to the boat ramp. I was holding the throttle just enough to keep the ski moving(about 5mph). It would run fine for a couple seconds, then run rough for a about 10 seconds. It did this the whole way back to the ramp. I did notice it was blowing a little more smoke out the back than usual.
For that couple seconds it ran good, i gave it full throttle, and it was perfect, like nothing was wrong. then would just run bad again.

After the over heating thoughts, i said, must be fouling the plugs, but it would come good for a few seconds(as mentioned) and would accelerate perfect. Obviously i checked and changed the plugs, but still the same.

Thanks for the tips, i never really rev it out of water, only when I'm flushing it after being in salt water, just a couple revs with the hose connected.

Are the rave valves known to clog up, and is this common. Ski has around 140hours.

Thanks

Sam

 

[Bruce MacKenzie]

May be MPEM

I've got a 99 GSX L that did exactly the same thing. It turned out to be a faulty MPEM. The MPEM worked fine for 10 to 30 mins and then it would break down. Next day it would do the same thing. You might try to borrow an MPEM or get one on EBAY ($200). Yours is a 278001499 which is the same as in my 99 GSX L. The 98 and 99s are not interchangeable.

I've also got a 98 GTX L that runs away every time I start it out of the water, I'm glad to know this is a common problem.

 

[Dr Honda]

Yes... it could be electrical. If that's the case... it can get expensive. For giggles... try this... Remove the spark plug boot, and cut your wire back about 1/4 inch. ( about 6mm) Some times, the wire cooks at the connection at the boot. Cutting it back to fresh wire is known to solve some light ignition issues. I had a similar problem with my Genesis. The spark wire was cooked at the coil, and the engine would cut one jug, in and out.

The runaway problem doesn't happen all the time, and it is rare. The problem is that there is extra carbon in the heads, and there is a lean condition just off of idle. So... when you rev it up, and start to pull the throttle back... the extra heat in the head will burn the fuel at a higher timing, and cause it to rev out of control. AND... since the engine is "Dieseling"... killing the ignition won't shut it off. BUT... it will never do this in the water, when the pump and engine are loaded.

This can be fixed (normally) by making the pilot circuit richer, and cleaning the heads.


The RAVE valves should be cleaned every year... and if you are using oil other than SeaDoo oil... they may gum up faster.

 

[pazzo]

Thanks Bruce. So the 98 and 99 are not interchangeable, but what about other years? 99 & 2000/01/02? i know the 03/04 are fuel injected and will most likely be different.

Tony, i have never heard of a ski 'running away'. Very interesting piece of info thanks. Just out of curiosity, if you don't cut the fuel, will it just keep running at full throttle until it over heats/seizes?

I'm leaning towards the RAVE valves over electrical, and so is my wallet
I don't think they have ever been cleaned, well certainly not in the 4-5 years I have owned the ski. We always use seadoo oil.

 

[flip6]

Sorry you've got issues with your xp. I've had about every issue with my 98 xp so just like to throw a few things your way

- probably not the raves but clean them anyway.
- check any rubber pipe areas of the exhaust - they can delaminate internally and partially block the exhaust. This could be a transient problem like you describe
- mine had similar issue two days ago and was exhaust bolts had vibrated loose. Smooth water was fine - in chop wouldn't go over 4000 rpm because chop caused exhaust to move and let water into the cylinders.
- i'd change the plugs cos it's cheap and easy
- check the fuel filter
- you mentioned more smoke - could the oil pump be overdosing 2 stroke oil ? (can't see how) Try disconnecting pump blocking pipes and trying a tank of premix. Long shot but depends how desperate you get

I've the running away issue out of the water. Scared the puss out of me the first time it happened.

good luck
Phil