250 ox66 Only reaching 5000 RMPs????

[31jupiter]

Hello:

I have a question regarding the 250 ox66 engine RPM range. I am only getting 5000 RMPs, is that the max on this engine? I was assuming it was 5500? And where should I begin checking to fix this if 5500 is what I should be getting?

Thanks in advance.

[99yam40]

either you have a motor problem, a set up problem, or it is over-propped for the load you are running