1992 yamaha 650 LX throttle problems!!!

[morey0928]

i have a yamha 650 LX 1992, and i have run it 2 times in the water. the first time it was sluggish and i took it to get it looked at, and i got a new impeller, intake grate, and lock ring. the second time i took it out (yesterday), it did fine for about 30 minutes, hauling some ***, and then it started to do the same thing as before, you would give it gas, and it would be real sluggish, and the engine would not top out. i rode it to shore, and got turned it off for about 5 minutes. then i started it again and went full throttle, and it took off very very fast and the engine topped out and i was flying over the water. then i let off the gas to idle, then tried to go full throttle again, and it was sluggish getting up to speed, and would not all the way top out. it sounds to me like it is aat about 70% engine speed compared to when it was going fast. the longer i rode it trying the throttle again and again, it just seemed to get more and more sluggish, and i could not get it to top out again. The guy that fixed it said that it would need a waterbox because he showed me the the one in is was fiberglassed because it was cracked. He also said i had an exhaust leak in the engine compartment, and could these two things be the problem with acceleration and my top speed? or is is something like the carb.? the compression the guy said was at 140, so i was good with that, so anything would help me, cause i want to get back out on the water. Thanks

[Technical Support]

Re: 1992 yamaha 650 LX throttle problems!!!

Yes any exhaust leak including the waterbox, would have adverse effects - however you would probably have worse performance than you describe, and the hull would be filled with smoke. If you saw no smoke I would recommend you rebuild the carbs.

[56mulberry]

Re: 1992 yamaha 650 LX throttle problems!!!

My 90 LX650 did something similar and it turned out to be the fuel pump--which on yours is integrated into the carb. Mine was stand alone but did the same thing--had a torn diphragm. DOUG