Engine compression 99 sportster lx

[Sirskisalot]

I performed an compression test on my 350 5.7L carb indmar.

190 psi on six cylinders and 170psi on two cylinders. Is the pressure difference a problem? I'm having problems hitting max rpms at wot. Won't go above 3400 rpms and should go 4500 rpms. The prop Is 13x13x1 1/8. Any suggestions would be appreciated.

[sgt1970-442]

I performed an compression test on my 350 5.7L carb indmar.

190 psi on six cylinders and 170psi on two cylinders. Is the pressure difference a problem? I'm having problems hitting max rpms at wot. Won't go above 3400 rpms and should go 4500 rpms. The prop Is 13x13x1 1/8. Any suggestions would be appreciated.

only 20psi drop on a couple of cylinders will not cause the problem your discribing.

might want to do a leak down test on the cylinders and check that the carb butterflys

are open all the way.

when did you start having problems with the wot? did it over heat or did you change anything?

[Sirskisalot]

I have own this boat for a year. I thought it should turn more rpms than 3800 rpms. I did a tune up on it plugs wires rotor cap filters the motor seems to run great. Could changing my prop from a13x13 to a 13x12 or 13x11.5 let my motor produce the 4400-4800 rpms that it should? I have not performed a leak down test.

[99response]

May be time for a carb rebuild, also check that the throttle plate is opening up all the way.

-Chris