1996 GSX 787 Engine issues

[Yamaha90]

last year spent over $700 checking up on the ski, new intake grate and impeller and battery and all that and i suck up a small piece of rubber that made its way into the engine and blocked the cooling system. this guy took the head off, i found the blockage and he put the head back on. few weeks or a month and a half after it started running like crap. drinkin oil and fouling spark plugs. what is the problem? compression was check recently to be good and some mercruiser machanic said a new set of spark plugs and she'll be good.....i told him i went though spark plugs like red cups at a frat party and thats not the whole problem... i don't know. i'm thinking about trading it in so if it runs fine now in the drive way just trade it in/sell it? but i don't wanna sell someone a problematic ski you know... can you guys help me out?

 

[seadoosnipe]

Rotary chamber....

I'm getting a lot of this lately. Seems to be a problem mostly from skis that sit up, without being turned over.

On the crankshaft, you have a worm gear. That gear drives the rotary valve, which is the valve that spins opening and closing the carbs intake system, like a set of reed valves.

This worm gear is in the middle of the crankshaft, between the two piston connecting rods. This chamber is filled with your 2 cycle oil and is seperated from the combustion area by an oil seal on each side, one on the pto piston side and one on the mag piston side. If they go bad, the oil will bleed out into the combustion area.

The oil is supplied to the rotary chamber from the bottom of the oil tank to the port side of the engine. The return (vent) is on the bottom of the starboard side, under the carbs and that hose re-attaches to the top of the oil tank, where the vent is.

These seals will have to be replaced and that means pulling the engine and splitting the casing..........

Yeah, I know, you didn't want to hear that. Sorry for your misfortune.

 

[Yamaha90]

so most likely a ful engine rebuild would most likely fix that... does anyone know what the would run about? i'm really contemplating a new/newer ski so this crap doesn't happen..

 

[Yamaha90]

i've decided to keep the ski unless a really good deal comes around, but until then while having the ski get worked on should ni have them just deck it out with new paint too while the whole thing is apart anyway? that way it'll look alot better/cleaner and when it's done getting worked on it will run great and i won't have any reason to get a newer one. too expensive anyway any opinions?

 

[seadoosnipe]

Engine......

You can get a new OEM remanafactured engine with a one year, no fault guarantee for $850.

 

[Yamaha90]

how much is a 951cc engine? although the ski is fine at about 55, a little more power would be good, and where would i get these engine prices?