whats the lowest amount of compression the Polaris triple fuji motors will run on?

[55evinrude]

Hi there i am looking at used cheap Polaris jet ski's with the fuji motors in them and yes i know they have problems so you don't have to tell me all about them lol. but i know 135psi is what they are on fresh rebuild but im wondering what a decent compression reading should be and whats the lowest they will run on/rebuild point. if someone could tell me that would be great. thanks

 

[Fireman431]

Re: whats the lowest amount of compression the Polaris triple fuji motors will run on

I've seen PWC engines anywhere from 115 to 150 PSI. As long as all cylinders are within 10-15% of each other, that's the biggest sticking point.

 

[slag]

Re: whats the lowest amount of compression the Polaris triple fuji motors will run on

the polaris triples themselves aren't really bad motors. The main issue is the fuel pump cannot deliver fuel to all 3 cylinders so you should upgrade to a 3 ouput fuel pump. Otherwise, you run the risk of leaning out the MAG cylinder and burning a hole in the piston. There can also be some crank twist, but its not horrible.