Waterpump mercruiser 165

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

 

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.

 

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.

 

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

 

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

 

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.