Motor won't run at high rpms

[marlon123]

i'm in a quandry..here is the situation..

1999 25mshw motor..

a couple of months back, while on a long run down the lake, the water impeller broke apart and the motor overheated to the point where it shut itself down to low rpm..

there was significant damage to the power head so I replaced the head + gasket and exhaust covers + gaskets..

compression is fine..spark is fine...carburation is fine...there are no water leaks that I can see..all wires are properly connected..but I can't get the motor to run faster than Idle speed..it looks like maybe the timing is not advancing with the throttle, but I am stumped

any suggestions??

[marlon123]

Forgot to mention that I replaced the water pump assembly..

I meant that there is no water leaking, i.e. coming out I
in places that it is not supposed to ..

I posted here to get the advice from some expert

[99yam40]

Those guys are just spamers, report them when you find their posts.

Check the timing with a timing light and see if that is the problem.

what was the compression after the overheat?
over heat will cause piston and ring problems.

Did you pull and replace of at least test the thermostat. It would be good to flush out and inspect motor insides for pieces of rubber impeller.

If it is advancing the timing, then I would be looking at the carbs