951 Engine Problem

[yogibear49341]

I just bought a 99 seadoo xp limited. I rode it for about 5 hours and it had about 40 hours when I bought it. I was riding at about WOT when the engine shut off and I coasted to a stop. I thought I was out of fuel so I switched to the reserve. While riding home at out 55 it did it again but I made it home. I added more fuel and went out riding again. After about 20 mins, it did this again. It happened about 10 more times and each time, there was no unusual noise or problem I could detect. I was able to fire it back up and ride for a few hundred feet and it would happen again. What could this be?

[Bill O'Neal1]

Re: 951 Engine Problem

Wow!

Not to be too critical, but did you think it was going to cure itself? You possibly siezed it about 10 times if you have someting like a clogged up fuel filter in the carbs. I hope for your sake you find a loose wire connector, like one of the big connectors on the MPEM. First do a compression test to detirmine if it was siezed. You should be seeing around 140 plus or minus 5 psi on BOTH clyinders.

[Technical Support]

Re: 951 Engine Problem

In the future...yow...every time your engine stops like that...unless it's electrical (hardly ever is) - you are doing DAMAGE. It adds up too. You can go from a $350 top-end job, to a $1100 motor, to a $2500 motor/cases/reeds/etc. after you blow a hole through block from continuing to ride it DAMAGED.

This isn't to harp on you, more for everyone else reading who is under the same assumption you are - that these engines just suddenly stop, and it's OK.

[yogibear49341]

Re: 951 Engine Problem

I heard nothing unusual with the engine and it was as if it had run out of fuel,but with no sputtering. Every time it occured it was in the same hull position and I thought the pickup moved away from fuel. When I bought it, the compression was only 120 on both cylinders and this was 5-6 hours before the inccident.
If I did seize a cylinder,how much to fix and what might have caused it?
Also, I was told to run premium fuel and sythetic seadoo oil. Is that right or wrong? Is there anything else I could have done wrong that could have messed it up?

[ShawnXB]

Re: 951 Engine Problem

Take it to a shop and have them test it with a decent compression gauge. It's possible that the whole reason they sold the ski in the first place is because it had seized on them before. Especially if it really only had 120 psi.

[Bill O'Neal2]

Re: 951 Engine Problem

I don't think this was anything that you would have known to avoid. The gas and oil you used did not cause this problem.
The 99 models suffered from bad fuel lines in certain parts of the country that use fuel additives in the gasoline. The internal materials of the fuel lines may have rotted and clogged up the internal fuel screens in your carbs, or some other problem like a bad amp connector is losing power to the ignition. There are a few things that can cause a ski motor to shut down.

Your compression, if really 120 psi, is an indication that the motor has seized the pistons in the clyinders. The motor will sieze, then cool off in a few seconds, refire then sieze again, over and over until a piston breaks. All of this is caused because the motor may not be recieving enough fuel, too much air, and is overheating the pistons.

[yogibear49341]

Re: 951 Engine Problem

When I first purchased the ski 2 weeks ago, the very first thing I did was take it to a mechanic that I trust. He checked the compression as well as the pump and the driveline in the ski. I had it checked by the mechanic before I had even rode the ski. He knows more about boats motors,but he,his son, and another jet ski mechanic are bombardier trained. The jet ski guy,who I don't know,checked it a few days ago, and said that a cylinder is seized,not both but one. It apparrently didn't have oil.

Is this a problem with the oil injection or carbs or what? I was stupid enough to break it,because I didn't know what I was doing. Is there anything important I need to know that no one told me and how much should this cost me? You guys are more help to me than the dealer and my mechanic combined.

[ShawnXB]

Re: 951 Engine Problem

If it didn't have oil, then it's an oil injection problem. Are you also saying that it had 120 psi when you bought it? If so, then see if you can take it back. If not, then you may be in for a costly repair. But that kind of depends. You may be able to get away with a top-end job only. This probably depends on the number of times it's been seized, and whether a single cylinder was seized. INAM, but if you have oil problems, it would seem that both cylinders would not be getting oil, and not just one...Someone with more knowledge about these oil pumps can give a more definitive answer though.

As it sounds like lack of oil really was the problem, you should consider going premix. It costs $15 for a block off plate. The conversion is easy to do (search the forums). Read the tech article as well.

[yogibear49341]

Re: 951 Engine Problem

The "jet ski guy" apparently really knows alot about the bigger jet ski motors(951 sea doo-1200 yamaha ect.) He said to me in a brief conversation, that only one had no oil. I could be wrong,but I think only one. I would prefer to keep oil injection if possible. How much will I be having to spend? I don't have thousands to puut into a new motor.

[Bill O'Neal2]

Re: 951 Engine Problem

Only one what had no oil?

[yogibear49341]

Re: 951 Engine Problem

That is what I thought he said. My ski is about 200 miles away and I will get the full story on thursday,my day off. I will go check it out and make my decision as to what I am goin to do. I may call again tomorrow. I know more about car engines(4 strokes),but 2 strokes baffle me. I couldn't figure it out either.

[xpcanada]

Re: 951 Engine Problem

I think hes saying only one cylinder had no oil.

[yogibear49341]

Re: 951 Engine Problem

I think hes saying only one cylinder had no oil.

That is what I am saying he said to me. He told me it had no oil in only one cylinder and that only one cylinder seized.

[1fastski.com]

Re: 951 Engine Problem

have who ever is checking it out to look at the rave hose close to the block , ive seen a few with holes in them and couse lean problems ,

i just built a 98 GTXL that the guy paid a dealer to go over and the dealer said all was good so the guy bought it , he used it 2 times then it sat for 3 weeks and locked up from water leaking in the orig gaskets that should have been updated , i cant beleave a dealer missed that and he didnt even have a rubber ring on his pipe .

PS keep your injection system not many fail due to bad pumps , more from lack of maintance .

[yogibear49341]

Re: 951 Engine Problem

Is there anything else specific I should have the mechanic check?
I want to keep the oil injection even though it costs more to fix. I love this jet ski even with the few hours I have had on it and I want to fix it right,but as cheap as possible. Is there any way I could rebuild the top end(minus machine work) myself? I have rebuilt a couple of auto engines, but never a pwc motor or anything like it before.