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marine engines

Michaela521's Avatar

Join Date: Sep 2004
Posts: 90

10-11-05, 09:45 AM   #1  
marine engines

How do you tell if your marine engine is a seawater (raw-water) cooled model or a closed cooling (coolant) model. What should I look for and where should i look. Thanks alot

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thezster's Avatar

Join Date: Aug 2005
Posts: 2,268

10-11-05, 12:24 PM   #2  
Inboard, inboard-outboard???? Small boat, large boat (it makes a difference, larger boats designed for salt water use are more prone to a closed system.

If you have a closed system, there will be a heat exchange system somewhere in the engine compartment, relatively large. If it is an open system (most are) - you will find a hose directly from the water pickup to the engine. On an inboard, it's easy to find, locate the water strainer on the bottom of the hull and follow the thru-hull connection and connecting hoses to see where they go. On an inboard/outboard, it's a bit more difficult (just a little bit) determining which hose from the transom bellows is the cooling water hose.

If that hose, from either system, goes directly into the engine after the water pump,(exhaust manifolds for pre-heating, or thermostat housing for non-preheating).... it's an open system. If that hose goes into a heat exchanger - it's closed. Follow the hoses.... it's pretty much common sense once you start tracing them.

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Last edited by Sharp Advice; 10-16-05 at 07:07 AM.
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