Yamaha 1999 250 OX66 running hot

[jfbetz]

I have a pair fo these motors on my rig. A couple months back, both were rinning hot only at low (below 1500) RPM's. Changed out Poppit Valves and 1 engine corrected. Of the remaining possibilities (water pump or T-stats) which is more likley to be the culprit, or is there something else to consider. When above 1500 RPM, the engine runs normal temp. per the temp. gauge.

 

[matt2002]

Re: Yamaha 1999 250 OX66 running hot

When was the last time you changed the impellers ? Maybe they have a "set".

 

[jfbetz]

Re: Yamaha 1999 250 OX66 running hot

Impellers were changed out in May of last year. I usually get a solid 2 years out of them, and even then when I change them out, they are not terribly set.

 

[JUSTINTIME]

Re: Yamaha 1999 250 OX66 running hot

i would do t-stats and clean poppet