1999 GSX limited revs but wont go

[Jay146992]

I took my GSX out on the lake and it ran good for about 10 minutes but then started slowing down. It will rev up to 6,800 but wont go faster than 10 mph. When I give it full throttle I can hear water rushing underneath the ski but it won't take off.

Any ideas? Thanks in advace

 

[mtrainer]

Check your wear ring around the impeller

 

[donkey]

sounds like its cavatating,,check the clearance between the impeller and the wear ring,,i think lou said it should be .020,,or about a nickle thickness,,i also saw a beach towel stuffed in the intake last week,,same result,lol

 

[Jay146992]

I forgot to mention that before I took it out I just replaced the oil tank due to a leak. I never blead the oil pump/lines. Before I replaced the tank it ran great. So now I'm guessing blown engine? FML.

 

[mtrainer]

Check you compressions. How long did you have it running after your replaced the tank?

 

[Jay146992]

Check you compressions. How long did you have it running after your replaced the tank?

I'm going to do that tomorrow. I had it running for about 10 minutes.
When I first started it up after I replaced the tank it was hesitating when I would give it full throttle. It would take a second then just take off. Sometimes if I would give it full throttle it would stall.

 

[Jay146992]

I rented a compression tester from autozone and got 120 psi in each cylinder. Don't know how accurate the gauge is but both of those numbers are the same so I'm guessing the engine is ok?

Now how do I bleed the oil system? Any other ideas on why the GSX would hesitate when I give it throttle?

 

[Strizzo]

120 on a 951 is about when it's time for a rebuild. BUT since both were exactly the same, I'd check it with another gauge before tearing it apart. Even new rebuilds will have a small variation between the cylinders.

Bleeding the oil I'm not familiar with on the 951, but you'll want to open the bleeder screw to let any air out of the pump, then to clear air from the injection lines start the motor and keep it at idle while holding the lever on the pump at wide open while watching the lines as any air is pumped out.

A hesitation off idle could mean you need a carb rebuild or it could be as simple as a non functioning accelerator pump.

 

[Jay146992]

120 on a 951 is about when it's time for a rebuild. BUT since both were exactly the same, I'd check it with another gauge before tearing it apart. Even new rebuilds will have a small variation between the cylinders.

I tested the compression when I first bought it and it was 120 in each cylinder and ran great. It isn't exactly the same, I think one is 120 and the other is 122 but they look pretty close.

 

[spx800]

ideally 130-135 is what you want to see on a 951.

 

[mtrainer]

Yeah its a little low. Check the accelerator pump. Its the little lever on the side of the carb, when you move it, it should squirt gas out of the little nozzle in the carb barrel. Did you check your wear ring yet to see if it was worn and thats why it only is going 10mph?

 

[Strizzo]

That severe of cavitation warrants looking at the carbon seal and floating ring, no matter how bad the wear ring is, it's getting some help at cavitating that bad

 

[mtrainer]

Also check the sealent between the haul and impeller housing and between the impeller housing and the part that connects to it

 

[Jay146992]

Well I just tested the compression on my other Yamaha jet ski and it was 120 in each cylinder also

I did have a good look at the ski and there was a huge piece of plastic wrapped around the impeller, so I'm guessing that was causing the problem.

Now I just need to bleed the oil system. This may sound like a dumb question but where is the bleeder screw? I don't even know where the oil pump is.

 

[LouDoo]

You might want to check, remove the steering nozzle, betcha the huge piece of plastic is your old wear ring. If the wear ring looks O.K., check it with a feeler gauge it should be not more than.040" about the thickness of a dime.

Lou

 

[Jay146992]

You might want to check, remove the steering nozzle, betcha the huge piece of plastic is your old wear ring. If the wear ring looks O.K., check it with a feeler gauge it should be not more than.040" about the thickness of a dime.

Lou

You're right, It was the wear ring. Is that a pretty easy DIY?

 

[Jay146992]

Can anyone tell me how to check the accelerator pump and bleed the oil lines? I don't even know where this stuff is located in the engine compartment so any help would be appreciated.

 

[mtrainer]

number 63 is the accelerator pump

 

[LouDoo]

You're right, It was the wear ring. Is that a pretty easy DIY?

The wear ring is not a bad job at all, actually I'm in the process of changing the wear ring in one of my ski's. A couple of pointers, use an OEM wear ring, aftermarket wear rings are hit and miss, and also change the neoprene seal is your ski has one. Here's a thread on the subject.

http://www.seadooforum.com/showthread.php?30720-How-To-Changing-Your-Wear-Ring

As far as bleeding the oil system, there's a screw on the oil pump you need to remove and then let the oil flow until there are no longer any bubbles in the line, you will probably need to download a manual for the details, sorry I'm not that familiar with a 951. After you bleed the pump run at idle with the pump full open until there are not longer any bubbles in the injector lines. The oil pump is on the mag. cover.

The accelerator pump is part of the mag. side carburetor unless you are not getting fuel, or you plan on rebuilding the carbs. I would just leave it alone.

Lou

 

[Jay146992]

Thanks for the help Lou!

Does anyone know if I have to remove the exhaust to access the pump? I can't get to it.

 

[LouDoo]

You shouldn't have to remove the exhaust to get access to the pump, the pump removes from outside the ski. On the new style you don't even need to remove the hoses, it's all done from outside the ski.

Lou

 

[Jay146992]

You shouldn't have to remove the exhaust to get access to the pump, the pump removes from outside the ski. On the new style you don't even need to remove the hoses, it's all done from outside the ski.

Lou

I'm talking about the oil pump. It seems like the exhaust is blocking it. Any ideas?