what should the rpms be ...

[gcha1727]

On a 787 motor my compression on mag at 150psi and only 135psi on the pto side.

Will this motor only reach 5500 rpms under load (on water)???

Yes there is some cylinder work needed at this time. I would like to know if I may have more problems..carbs/cavitation etc..

Thanks

 

[LouDoo]

Well, your compression on the mag side is perfect, 135 is marginal, the difference in compression you're right at 15% is what bothers me. Do you know how many hours are on the engine? You might get by with honing and rings.

Your engine ideally should top out at 7000 rpm, however anything over 6750 would be considered normal.

It's impossible to tell from just a compression reading if you have fuel delivery problems or cavitation. However it's been my experience that the rpm's will drop off slightly with cavitation but not to 5500 rpms. Check the condition and clearance of your wear ring, .040" and if you have grey fuel lines replace them and clean the fuel system.

http://www.seadooforum.com/showthre...el-Delivery-Problems-low-revs-bogging-surging

Lou

 

[Dr Honda]

When was the last time you cleaned your RAVE valves?