Help...Overheating

[jgliatta]

Would anyone know what is causing this problem, or how to fix it?<br /><br />I have a 225hp Mercury, and it begins to heat up at Idle or when I run the boat in reverse. The water stream looks strong, and the temp. is fine at running speed. But, if I let the motor idle a while, it heats up to buzzer level. I changed the thermostats, and the high pressure diaphram. Could it still be the impeller even though the water stream is strong??? Help please....

 

[Reel Appeal]

Re: Help...Overheating

Fishforever,<br /> Yes,the impeller could still be the problem.When sitting still or moving slowly the water pump may not be delivering enough water.As you go faster you will get better flow and better cooling(because water is being forced into the lower unit).This is a problem though and if not repaired could lead to powerhead damage.The impeller could be missing vanes,dryrotted etc..If the water pump has not been serviced in a year or more,replace the impeller with Mercury parts.

 

[jgliatta]

Re: Help...Overheating

How do I know if I have to replace just the impeller or whole water pump? Is it difficult to do this?

 

[clanton]

Re: Help...Overheating

Remove the pump and inspect. check housing for warpage and wear plates for wear. Service manual will indicate the spots to inspect.

 

[finadic]

Re: Help...Overheating

Had same problem with opti max 200 pulled impeller everything looked fine with it but replaced anyway. That was the problem. If your gonna pull lower replace it.