cooling question 140hp gm mercruiser

[mphy98]

ok, i will show my ignorance here but, i thought the engine had a waterpump in the front of the engine like a car waterpump. what is all the talk about impellers. do all io's have one of these in the lower unit? if so is it easy to replace? diagram would be good. 1979 vintage. thanks bob

 

[Don S]

Re: cooling question 140hp gm mercruiser

The pump on the front of a marine engine is known as a circulation pump. On cars it's called a water pump. On boats the raw water pump (the one that feeds outside water to the manifolds and sometimes the engine on a raw water cooled boat) is used to cool things instead of air blowing over the engine and a radiator.
Believe it or not, the long block of a marine engine is similar to automotive, but the sub systems are all completely different.

 

[Bondo]

Re: cooling question 140hp gm mercruiser

if so is it easy to replace? diagram would be good. 1979 vintage

Ayuh,....

If you're Pretty Handy,+ have a decent Tool Kit,... nothing to it....
If you're Not,+ Don't,.... Well,..??

The Diagrams are found Here,...
It's a Massive file,... It could take Hours to download, depending on your connection...

 

[Don S]

Re: cooling question 140hp gm mercruiser

You need #3 for your engine and #4 for your drive.
Both (as bondo mentions) are huge. Bondo's link goes to #3

http://forums.iboats.com/showthread.php?t=251571