i have a 93 jetski 750 xi ss. the problem i have is it starts right up and will run great and rev up fine on the trailer with garden hose hooked up and water pisses out the side nozzle fine. as soon as i put it in the water it only idles for about 2 minutes and stalls out. it is hard to start in the water and if u try to give it gas it boggs out and stalls. i was only able to get to rev up enough to get it up on the dry dock a few times but stalls right out. then i tryed to leave it half in the water half on the dry dock so the back portion is in the water for cooling, i was able to keep it running for about 5 minutes at 1/4 to 1/2 throttle to see if after warming up it would do the same thing. but instead i noticed that the water coming out the side was drizzling and steam coming out at the same time. can this be the head gasket is bad and only when i put a load on the jet pump in the water the engine compression drops enought that it stalls out? i dont think its the carbs cause it was running great acroos the rpm band on the trailer, this is only in the water this problem. anyone else have this problem?

 

If your head gasket is bad you should notice smoke in the exhaust when running it off the hose. I know there is alot of stuff flying around but if its smoking, you will know it. My guess is going the be the carbs. It doesn't take much fuel to ping the rev limiter with no load on the motor, but when it actually has to do some work and move some water around it might not be getting the right fuel flow to keep it alive. Try cleaning the carbs and let us know if it helps. It sucks that you gotta drive all the way to the lake to find out if it worked.

 

actually there is alot of smoke coming from the exhaust and there was some smoke coming from the side water nozzle too before it started steaming. I didn't think too much about it cause I thought the mix might of had too much oil in it. I know you might be saying why is there a mixed fuel , someone before I bougt it eliminated the entire oil injection system and had been premixing the entire life of the machine, sucks premixing but I got it for a ridiculious price with the trailer and cover so I guess I can deal with it till a newer jetski. I'm gonna replace the headgasket between today and wednsday. I'll let you guys know if it worked, if not i'll be pulling the carbs and checking compression.

 

mine was doing the same thing rebuild the carbs it worked for mine. i have 2 of the same skis and they were both doing it rebuilt the carbs and they ran great. i noticed that i have to tun my mixing screws really rich for them to run right.

 

Nothing wrong with a premix, at least you dont have to worry about the oil system failing and turning your engine into an extremely effective anchor. Let us know how the gaskets work out, good luck on the fix bro!

 

hello everyone i am new to the site. I realize this is an old post but i have the same issue. i have cleaned and "rebuilt" the carbs with kits from sbt. still same issue. i was given this ski and have not put much time in it as i have others that interest me more. so my question is about a filter. is there a filter i do not see or is it only in the tank or otherwise. by the way compression is 155 in both cylinders. any ideas would be appreciated thanks.