I am new to riding a jetski and working on one. i have a kawa 650 sx and it has been acting up. i rebuilt the top end. new pistons rings and jug. i get it on the water and it wont get out of the water i have been adjusting the high and low screws and i got it to get out of the water but still only goes about 20 mph and takes forever to even get out of the water. then when i fall off the ski comes back to me and i press the gas and it stalls and wont start. can some one help me please
thanks mike

 

It seems like a carb issue. Clean it good and readjust. Also check for water in your fuel tank.

 

I have a 1990 650sx and I had trouble with it taking forever to get out of the water and plane. It happened right at the end of the riding season about 2 years ago. I assumed the engine was ok and took off the jet pump. I changed the impeller (to stainless)and some bearings and seals and it ran perfectly after that. Sometimes you get lucky I guess. There are 2 main concerns with the jet pump, the stock aluminum impeller wears down over time and the clearance from the impeller to the wear ring is extremely tight. You have to get a service manual and a set of long feeler guages to check the clearance. If that clearance is too big it will reduce pumppower output.Secondly, you have to be sure the jet pump isn't sucking air. When you put it back on, it has to be completely sealed with silicone to the hull. Also, the bulkhead bearing/seal where the driveshaft comes thru the hull needs to be sealed with silicone so the pump doesn't suck air from the engine compartment. I should warn you, be sure this is the problem because you need to pull the motor out first and then slide out driveshaft before pump can be removed. As far as the stalling, make sure the idle is set high enough, if you set the idle on land the pump is not loaded down. Therefore when you put it in the water you lose over 200 rpm since the pump is pumping water. Good Luck! Hope this information helps. Now I just hope someone can help me with my stx 1100 diproblem I have posted.
Regards, Steve R.

 

You issue seems more carb related than impeller, you can go to the local dealer and look in the parts unlimited watercraft book. Find the fuel section and look for the rebuild kit that fits your model carburetor, the company (jet line) only builds two types based on diameter of carb 36 and 40 mm I think.. It will come with all of the diaphragms and orings. The diaphragms in your carb have hardened and are not pumping fuel correctly. This kit also had a diaphragm for the fuel pump usually mounted to the side of the hull on this model. Change that diaphragm also.

KEEP IN MIND DO NOT USE THE NEW SPRINGS WITH THE FUEL NEEDLE. THEY ARE DIFFERENT TENSIONS THAN THE OEM AND WILL SET THE POP OFF PRESURE DIFFERENTLY! USE YOUR STOCK SPRING!!!!
Hope this helps,
Jody