mercruiser 165 heating problem

[finisher88]

Mercruiser 165 inline six chevy,1978, recent rebuild, new riser,manifold cleaned, new T-sat,the engine water pump was cleaned & reinstalled,new flapper in the exhaust, impeller pump in the leg was new three years ago, with very few hours on it, ( 30 ) as the engine was tired at the time. On start up, allowing time for it to warm up, the temperature will climb to to almost the red zone on the guage, if I rev the engine to 1500 rpm the temp will go down to normal, then I can run it at idle, but at low rpm it tends to rise in temp, when running at at 2500 to 3500 rpm the temp remains at normal. After a long run at cruising speed and then down to idle the temp will climb to almost the red zone and I have to rev it in neutral for several minutes to get the temp down. After writing this I am thinking that the impeller pump needs to be changed, any comments.

 

[Bondo]

Re: mercruiser 165 heating problem

impeller pump in the leg was new three years ago,

Ayuh,.... That's where I'd start....

 

[ENSIGN]

Re: mercruiser 165 heating problem

Low Water Pressure,start With The Impeller.

 

[finisher88]

Re: mercruiser 165 heating problem

Changed the impeller working great. Problem solved.

 

[Camille]

Re: mercruiser 165 heating problem

I have an 88 renkin cuddy 20ft. I put it in the water and almost sank it because there was no drain plug. I put in drain plug, took it back to water. the engine runs fine, then all of a sudden it starts to smoke in the cuddy. I look to the stern side and see water coming into the boat. the engine is too hot to start so i didnt force it. I vertially swam the boat back to the dock; by then its full of water all the way into the cuddy. There is no hole in the hull and doesnt seem to be at the transom but i can't see behind that. There is a hole in my bilge pump hose, but i didnt have it on. The 50/50 antifreeze that i filled the radiator with is now almost gone. After cooling, the boat starts on first crank on the water hose flusher, the temp remains fine. Where did the antifreeze go ,and where did the water come from into the boat? The hull is fiberglas. How can i tell if the transom is one of the problems for the leak?

 

[CheapboatKev]

Re: mercruiser 165 heating problem

Camille
Welcome Aboard..
Please start a NEW THREAD and post your questions there.

That way all responses will be directed towards your issues.