[pls3]

I recently had my 1995 polaris 650 standard jet ski serviced. It
was running great until sometimes when you give it full throttle it
will not go. You can pull the choke and then it will take off. It does
not do it all the time, it is hit or miss. It may do it from the start or you may be running great at full speed and all of a sudden it will slow down and eventually stop. I have to either pull choke all the time or gradually build speed, or never give it full throttle. What should I check? It is a shame because it runs great when this is not happening.

 

[JetskiMN]

Sounds like a colapsing fuel line...at that age of a watercraft the fuel lines get soft spots from age causing it to colapse as suchion from the gas runs through it...also check to see if there are any tight bends in your gas line...something may have gotten kinked. A colapsing line is difficult to find/detect and you just have to go and replace all the fuel lines. I'd try this first before messing around with the carbs.

 

[polarispa]

I would also replace the pump for a tripple output.