91 Yamaha Wave Runner III

[Basket Case]

:o I hope you guys don't ban me from the site??? BUT
1978 Nordic Jet - 460 Ford & Dominator - RUNNING GREAT
1991 Yamaha Wave Runner III - Starts and idles fine (no full throttle)
Good spark, new plugs, fresh fuel, pumping fuel, new fuel filter, throttle cable OK, 150# compression and holding, intake is clear of trash.
This thing starts and idles great but will not get up on plane.
I am baffled!!!
Any suggestions????????? I'm ready to set out on the curb for trash day.
Thanks for any help.
Basket Case

[Trailer Park Casanova]

The problems my friends had who owned waverrunners:
Ignition timing
Damaged impeller is the usual culprit.
Impeller is clear, but something went through it and the damage is causing cavitation. Inspect the cutting edge of the blades.
Clogged fuel line: Enough gas gets thru to run on idle and come off idle, but not enough to get up to wakespeed.

[Basket Case]

Thanks for the feed back. I will check the impeller, have not considered that. I also found a personal watercraft site with a good forum. They show some carb rebuild procedures. If the impeller is OK, I plan to tear down the carb and check the high speed jet and the internal filter which I did not know existed.

[uLtRADeNniS]

:o I hope you guys don't ban me from the site??? BUT
1978 Nordic Jet - 460 Ford & Dominator - RUNNING GREAT
1991 Yamaha Wave Runner III - Starts and idles fine (no full throttle)
Good spark, new plugs, fresh fuel, pumping fuel, new fuel filter, throttle cable OK, 150# compression and holding, intake is clear of trash.
This thing starts and idles great but will not get up on plane.
I am baffled!!!
Any suggestions????????? I'm ready to set out on the curb for trash day.
Thanks for any help.
Basket Case
It could be a bearing in your pump. Thats if the motor is a wot and you go no where. I had a similar problem.

[Mountainstone]

Jet pumps are very finicky; I agree that is most likely cavitation if the engine goes to wot but will not plane. Check for debris (even tiny stuff makes a huge difference), nicks in the impeller and the wear ring shrouding the impeller. I am not familiar with the Yamaha rig, but if the pump is sucking air from anywhere else on the ride plate you will get cavitation.

[Paul128a]

i have a couple of skis here, from sea-doos, a kawasaki, and a waverunner III.
My question is, what happens when you put the throttle up to full? Do the rpms go up without forward motion (cavitation), or you simply wont rev.
If you wont rev, that means you may have too much fuel going in the engine, a too rich condition, so the two-stroke wont rev.
If your engine sputters and dies in full throttle, you may have a shortage of fuel.
I do my own carbs and engines, so if you could describe whats happening, I may help you.

[Paul128a]

My usual adjustment on the WV3 is 1 1/2 turns out on the Low jet, and one turn on the high jet. This is with NGK B8HS plugs. What plugs are you using?
Start from there, run your ski in 1/4 throttle only and look at the plugs, they should be reddish brown. If they are too dark, close the Low Jet a little, if otherwise, open a little.
Then, run your ski wide open for about 10 seconds maximum, and check your plugs. If dark, slowly close the high jet until you get reddish brown.
Tan is supposedly the best color, but thats scary on reliability, so go a bit richer with reddish brown, you are safer there.
I also suggest going pre-mix on the WR3, running Quicksilver outboard oil at 40:1 to 50:1 is safest.
Hope that helps.

[wsuwrhr]

Where are you at?
I good friend of mine owns a jet ski shop and off road shop in Riverside.
Racer's Edge 951 681 1131

[78Southwind]

I had a similar symptom with my ’95 Sea Doo GTX. I found out through a friend that Sea Doo had a recall on the gas tank. I guess it was somewhat of a silent recall because the dealer I took it to didn’t even know that there was a recall on the gas tank. There ending up being a small crack in the gas tank and this caused a similar symptom as if the fuel line was clogged. I hope this helps good luck.