Waterpump mercruiser 165

[Danielsan]

is there a difference between a mercruiser 165 - 6IL -4.1L and a automotive GM 6IL - 4.1L waterpump exept the pricing?

I don't want to start a fire again on the automotive/marine parts

 

[tpenfield]

Do you mean the recirculating pump that is on the engine (not the sea water pump in the outdrive)? The only difference would be the impeller is made out of a better metal, not sure of the specifics or if it really matters. With a closed cooling system, it would not matter at all.

 

[Ike]

Yes there is. I made that mistake. I put an automotive water pump in. I was in a hurry and just wanted to get the engine running and didn't want to wait to get a marine pump. Went to NAPA. Installed it. Got everything up and running. Then I forgot about it for a few months until I noticed the temps starting to go higher than before. Checked everything and finally pulled the pump. It was already turning into a pile of rust. I got a new marine pump off the internet. 6 years later it still looked like new. Unfortunately in 2017 the head rusted out (46 year old engine) But I still have the water pump. If needed I can use it on the "new to me" 165 I had installed to replace the old one. Different metals. Yeah it's more expensive but will last far longer.

 

[Danielsan]

Yeah I imagine always the same story no automotive on a marine application... here in europe is just 5x the price of automotive... i must sau that the actual is quite rusty after probably as it is ad mid ‘70s engine and has a cast iron impeller

 

[7228sedan]

If your motor is freshwater cooled, you can use the automotive pump with some success. If saltwater cooled, don't bother.

 

[Ike]

This is what the old water pump looked like.

This is the new marine water pump. As you can see from the photo, the impeller is a different material (some sort of marine bronze), and a different configuration. I am told it is a higher capacity than the auto pump.

However I have discovered that some components on the engine are the same as the auto components. I just changed the solenoid on the starter, and it is the same as on the auto version. The starter is marine but the solenoid is the same.