Mercruiser 5.7 '95 Overheating

[STARK912]

Last time i took the boat out i was cruising and the temp shoot up. I backed off and the temp dropped. It has done this several times. Today I changed the plugs then hooked the hose to the lower unit fired up to run the engine. i noticed that the one riser was warm and the other was extremly hot. I also noticed that the water was flowing better out the side that was cooler. Any thoughts on what is causing the engine to overheat. Thanks

 

[Don S]

Re: Mercruiser 5.7 '95 Overheating

When was the last time the raw water pump impeller was changed?

 

[STARK912]

Re: Mercruiser 5.7 '95 Overheating

It was changed a little over two years ago.

 

[Don S]

Re: Mercruiser 5.7 '95 Overheating

I would sure pull the impeller and check it (and replace it since most of the cost is the time to take it apart). Never know if you picked up a plastic bag and may have damaged the impeller.

Also pull the risers off and check that they are not plugged on either the inlet or outlet holes.

 

[carlfarey]

Re: Mercruiser 5.7 '95 Overheating

Mine has begun heating up a bit when I go faster and then cooling when I slow, but sometimes the alarm comes on when its hot, is that my impellar?


Thank you.

Carl.