1996 Sea Doo Issues

[kesslersxp]

(This was accidently posted on the four stroke section)
Hi i have a fully rebuilt 1996 Seadoo Xp,

I am having a problem where the engine will go the speed I want it to but then lose power and rev at a lower rpm then it should. This will happen on and off for about 5 seconds each. For example, I'll be going 30 mph and then the jetski will lose a decent amount of power and go down to about 15 mph (the engine will still go but just at a lower rpm then it should be at) then it will go back up to 30 mph and keep doing that. Btw this doesn't happen for a while I can usually ride it normally for about 30 minutes before this engine problem happens. I've checked the spark plugs and made sure the gas was turned on.

Does anyone know what this problem could be?
I can try to post photos and videos if that helps.

 

[mikidymac]

Did you replace the gray fuel hoses, fuel strainer, on/off valve and rebuild the carbs with genuine Mikuni parts? Sure sounds like it’s starving for fuel.

When it quits does opening the gas cap help? If the check valve doesn’t work it can build a vacuum and starve it of fuel.

 

[kesslersxp]

Did you replace the gray fuel hoses, fuel strainer, on/off valve and rebuild the carbs with genuine Mikuni parts? Sure sounds like it’s starving for fuel.

When it quits does opening the gas cap help? If the check valve doesn’t work it can build a vacuum and starve it of fuel.

Fuel Lines replaced, Carbs rebuilt with oem parts, fuel strainer is clean, on off valve has been replaced.

Also the jet ski doesn’t stop it just goes to a way lower rpm then it should. Like i’ll be full on the throttle and it would randomly rev down then rev back up.

 

[mikidymac]

If your confident it’s not fuel related it could be the voltage rectifier. They can cause all kinds of crazy things when they go out. You can unplug the red wire when it runs bad and see if that fixes it. It will run fine but you won’t be changing the battery so once it runs down the ski will be dead.

 

[Andrew_bearss]

Hi, I have a 96’ gts sea doo. It will rev but it will not accelerate. I have looked up some possible problems, and cavitation is a word I have found.

 

[mikidymac]

Hi, I have a 96’ gts sea doo. It will rev but it will not accelerate. I have looked up some possible problems, and cavitation is a word I have found.

Please start a new thread with your problems.
If it revs but doesn't go like a slipping clutch it is typically a piece of wood stuck in the pump or a wear ring that needs to be replaced.

 

[kesslersxp]

So we tried a new Voltage Regulator and the jet ski still had the same issue. I’m thinking it could be the Magneto/Stator since this issue starts happening after about 15-30 min of riding which could mean the battery isn’t getting any charge? This is a really big fix though. Any thoughts or suggestions?

 

[tingraham]

Check to see if it is charging out of the water. Put volt meter on battery and rev it up a little to make sure you are getting 13.5-14 volts dc.

Does it do the same if you just hold it wide open where it slows down and then will speed back up consistently?

 

[James96xp]

I have the same issue with power surging around towing speed, constant half throttle. apparently the 787 is notorious for having this issue. It seems like a fuel starvation problem to me. If it's calm out on the water and i pump the throttle and hold it coming back up on the throttle I can get it to hold a decent speed with no power surge. But if I back of the throttle even 1mm, the power will start to surge again. It's not a carb thing because I've already cleaned them, the lines were also replace so no problem with gumming up the filter. Could it be a tank ventilation problem? I will unscrew the gas cap next time I go out and see if it helps.

 

[James96xp]

When it's wot I do think it still has the same issue but a lot less noticeable. It might go between 95% power and 100%. It's hard to properly verify this issue because it's rare that the water is flat where I am so I'm not sure if the prop is all able to grab the water at a constant rate.