I've had this jet ski for about 3 weeks now. The first 4 runs were perfect! It ran very well with no issues.
On our 5th run, and about the 4th restart, the engine won't die down under about half speed. When I let go of the throttle, it just keeps going; fast enough to stay cruising on top of the water. I have to power down early and slowly coast in to the shore.

Under the hood I see that the throttle cable moves fluidly as I press the thumb throttle control on the steering column. There's no point where it hangs up that I can see. I took off the air intake from the top of the carb and see that the both metal flaps move smoothly when pressing the throttle and turning the choke off and on. I'm not experienced with carburetors so one thing I am wondering about is if the throttle flap should be fully closed when at idle or slightly open. Right now, it's slightly open at idle.

I've also tried adjusting the low engine speed on the right side of the carburetor and that had no affect at all. After starting up, the ski just revs up to the same level. The time I took it to the lake to test the low speed adjuster I took it out and around the lake. It runs just fine other then it just won't slow down. I can push the throttle and it speeds up to full speed with out hesitation. I ended up having fun on it for over 30 minutes and just had to be really careful when bringing it back to shore.

Can anyone help me out? I'm familiar enough with things to be able to follow instructions if someone is able to guide me along.
Thank you!

 

Forgive me for knowing very little about jet skis, let alone yours, but is there a choke mechanism that is sticking open? Is there just a little bit of slack in your throttle cable, or is it tight when the throttle is released?

Oh, and welcome to the forum. Hope we can help you figure it out.

edit: could also be a vauum leak.

 

Hi,
Thanks for the warm welcome. Both cables seem to be moving fluidly when I engage and release them. The vacuum comment may make sense. Would an over exposure to air cause my symptoms?

 

Did you get it resolved yet? I doubt it is a vacuum leak since you have full power. A high idle on the trailer is more typical of a vacuum leak. How is the engine temerature.... a vacuum leak results in a lean condiditon.... often overheats the engine. If you are uncertain, a full leak-down test can verify the vacuum leak problem, but they are a fair amount of trouble to conduct.
My bet is on the carburator's throttle mechanism. Be certain the butterfly valve on the throttle is fully closed. If you meant the low speed mixture adjust screw, when you were testing it, that has more to do with power at lower throttle setting.... more so than establishing a minimum speed setting.

 

Hi- no not resolved I yet. The butterfly valve for the throttle does NOT close all the way actually. So I guess that's my problem! how do you suggest I fix this?

Also, to address your other question, the engine isn't overheating. I ran it in the lake for over an hour with this problem and I had no issues other then the excessive speed.

 

I would think that if the butterfly valve isn't closing all the way, then you may have a problem with the throttle cables (sticking or adjustment) or the idle (not idle mix) screw is turned in holding the butterfly valve open further than it should be.

 

I agree with IDRIDR. Make sure the throttle cable actually goes a tiny bit slack, when you release the lever. Then a tab on the throttle shaft should be resting on the idle speed set screw. Also check the throttle lever on the handlebar. Some have an adjustment there too... but those are usually for max throttle (to keep inexperienced riders from going too fast. Worth checking into anyway, just to make sure the lever is functioning as it should.