'88 7.4 Alpha

S

Sorrento 25

Petty Officer 2nd Class
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Oct 9, 2006
Messages
181
I just bought this boat and the previous owner ran it with no thermostat stating that the thermostat restricted flow in warmer water temperatures and the lower unit impeller didn't flow enough water for a big block. The engine has new risers and seems fine but this bothers me. Any advice? High flow thermostat maybe?
 
Don S

Don S

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Messages
62,321
Re: '88 7.4 Alpha

Put the correct thermostat back in it. Without it, the cooling water circulates too fast and doesn't cool the back of the engine. Only the front portion (around the sending unit) runs cold, the rest is hot. The faster moving water doesn't disapate the heat as well either.
 
Bondo

Bondo

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Re: '88 7.4 Alpha

Ayuh,...........

And,.. You might want to install a Complete Waterpump Kit in the lower unit,.........
Sometimes Just an Impeller Isn't enough...........

That combo Should run Just Fine,........ As Designed...........
 
S

Sorrento 25

Petty Officer 2nd Class
Joined
Oct 9, 2006
Messages
181
Re: '88 7.4 Alpha

Thanks! Ordering correct thermostat and water pump kit for lower unit.

I suspect now it may be a salt-water related issue in the block. This will be a fresh-water boat from now on and I intend to flush it with salt-away when I winterize. Is there anything else I can do to improve heat transfer or eliminate existing corrosion?
 
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