Alpha 1 Raw Water Cooling Question

[Knot Waiting]

How fast should water flow through the engine block. I mean if the impeller in the outdrive is turning constantly and so is the water pump shouldnt it just run in and run out? Or does the thermostat open and close like a closed loop cooling system?

The reason I ask is because when I had it hooked to muffs I didnt have any water leave the exhaust for the little bit I ran it (shut it down because I got nervous).

88' Alpha 1 'r' 350 Merc

 

[jerryjerry05]

Re: Alpha 1 Raw Water Cooling Question

If your block has been drained it would take a bit to fill. Running on muffs the motor doesn't get as much water as in the lake.
The circulation pump just circulates the water that's in the block so there are no hot spots. The drive pump sends water to the thermostat that opens when it gets hot allowing cooling water in.The thermostat housing bypases the excess water to the exhaust manifolds keeping cool water flowing at all times.If the thermo only opened and alllowed water to flow when it got hot the manifolds would get so hot the rubber boots would burn.
How old is the impeller? An impeller that is over 3 years old should be replaced just as a precaution. They should be done at least every 2 years. Jerry