Personal Water Craft Forum banner

1999 760 Waverunner problem

2K views 17 replies 3 participants last post by  dlane123 
#1 ·
I am having trouble getting my jet ski up to speed on start up. It runs about 15mph and stumbles for a couple of minutes and then gets to 35mph. It use to go 47 mph. Any ideas.
 
#3 ·
I am having trouble replying, so here it goes again. I am not sure of the engine performance
or revs. The problem seems to be a carb problem in that it stumbles when I open the throttle
where it wants to die like it is getting too much air and not enough gas. What I can't under
stand is why this problem goes away after about two minutes. Don't this propeller slippage.
Any thoughts? Oh, I did rebuild the carb late last year. Dave
 
#10 ·
OK being perplexed is an understatement. I still have the problem of the jet ski only getting to 18-20 MPH. The normal speed is in the 40s MPH. On odd thing is that the speed gets up to 35 MPH occasionally. OK I have rebuilt the carb again. I was meticulous in the rebuild, did everything but recheck the pop off pressure which was OK the last time. I was very careful in the reassembly. I did not replace the needles and springs.

I checked the engine cylinder pressure, the pressure for each was 90 PSI. The spec for the engine output is kW (PS)/rpm = 66.2 (90)/6350. I believe the engine is OK. The jet ski body is great shape. The impeller is secure. Maybe I need another carb. Please let me know what you think. Thanks, Dave
 
#14 ·
Thanks for replying. Would it be reasonable to expect that both cylinders would degrade from 145 PSI each to 90 PSI equally? I am ready to place an order for a SBT engine based on your information unless you think I somehow measured the 90 PSI each incorrectly. Thanks for your help. Dave
 
#15 ·
What are you using for a compression guage? My suggestion would be to rent another tester from local automotive parts store and retest to confirm numbers.

Yes, some times they wear even or very close to even.

Don't order from sbt quality is substandard. Pwcengines a much better option.
 
#16 ·
I used an Auto Zone compression gauge but will get the loaner again. I will retest to confirm.

SBT vs PWCengine: How is PWCengine superior to SBT? I would like to hear.

I got two engines from SBT in the past and results have been good. Thanks, Dave
 
#17 ·
Superior in the fact I've seen missing crank/rod spacers in there cranks. Missing wrist pin/piston spacers. Incorrect main brgs installed. The list goes on and on. This is what I've seen. Search the pwc sites you'll find others with same sightings. I just don't trust them. There quality just isn't there. It's about a 50/50 Gamble and I don't like those odds. They fall back on there warranty. Witch then costs the costomer or mechanic the replacement cost.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top