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1997 250HP EFI - Port side runs cooler than starboard side

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  • 1997 250HP EFI - Port side runs cooler than starboard side

    Hi -

    First time post to this forum. I've been trying to diagnose a temperature issue. It is causing the enging to periodically surge until temperature comes up. This occurs after having been idling for a while, then taking off on plane. It will bog until temp comes up.

    Dealer said to check to make sure both sides of engine are at about 150 degrees when running at the dock. Port side is hot - too hot to hold hand on top for long. Starboard side is running about 40-50 degrees cooler. Water is clearly running through the piston's cooling chambers. I'm having a bitch of a time trying to figure out where/how.

    I have swapped thermostats and problem stays on starboard side, so it is not a thermostat issue. Also both are new at end of last year. At the dealer recommendation I have replaced the gasket at the water jacket on outside of starboard side pistons. In retrospect that was a waste of $30 because water leaking from there would have been visibly spraying. There is no place for it to leak to and flow to. Dealer's next recommendation is to check the power head gasket. I'm hesitant to do this because it's $60 for the gasket and I'm not sure it's relevant. Can anyone comment on the value of pulling the head off and inspecting?

    This is a minor problem, but as you may know these EFI engines are ultra sensitive to temperature, so I'd like to address it. I'm sure its affecting my fuel consumption as well as perhaps a bit too much fuel going to the plugs/pistons causing carbon build up. Not to mention the occasional bogging.

    Any other advice on how to water can flow through the starboard side would be appreciated.

  • #2
    Sorry posting topic was wrong. It's starboard runs cooler than port...

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