Hello I was thinking about purchasing a hunter 84 34 ft and was told that it has fresh water cooling? It has the 3gm motor. I thought all the early boats cooled with seawater? What should I look for when I test the engine?
Fresh Water Cooling
- Thread starter hunter healer
- Start date
the two cooling types are raw (sea) water and fresh (antyfreeze) water.
raw water cooling takes the water that the boat is floating in and circulates it through the engine block then out through the exhaust. Fresh water (bad name BTW) circulates antyfreeze through the engine block and water to water heat exchanger (radiators are water to air heat exchangers BTW) An engine pump sucks in water that boat is floating in and cools the antifreeze in the heat exchanger and then get shot into the exhaust.
About the only thing to check in a fresh water cooling system is the expansion tank (just like your car!) and that raw water is in fact coming out the exhaust when the engine is running. also check for a raw water strainer to keep fish and weeds out of the raw water circuit.
raw water cooling takes the water that the boat is floating in and circulates it through the engine block then out through the exhaust. Fresh water (bad name BTW) circulates antyfreeze through the engine block and water to water heat exchanger (radiators are water to air heat exchangers BTW) An engine pump sucks in water that boat is floating in and cools the antifreeze in the heat exchanger and then get shot into the exhaust.
About the only thing to check in a fresh water cooling system is the expansion tank (just like your car!) and that raw water is in fact coming out the exhaust when the engine is running. also check for a raw water strainer to keep fish and weeds out of the raw water circuit.
Bill's right (there I go again!
). It would be odd for that size boat to have a raw water cooled engine, but I am no expert on yanmars, but I thought the #GM series was freshwater cooled.
Help, someone correct me.
Thanks,
Stu
). It would be odd for that size boat to have a raw water cooled engine, but I am no expert on yanmars, but I thought the #GM series was freshwater cooled.Help, someone correct me.
Thanks,
Stu
hello there, i understand now how it works so the radiator and heat exchangers cool the seawater running through the block and the seawater pump is constantly taking in seawater and spitting it out through the exhaust, thank you CR
Hot off the scanner from my shop manual.
Close enough, ya still get a cigar :dance:.
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With the exception of the 1GM all the multi cylinder GM series engines seem to be fresh water cooled. I guess the size of the boats and production budgets could not accommodate a water pump and a heat exchanger for small 1GM.
Christian,
My H34 is a 1983 and has a Westerbeke. However, in terms of what to look for in a FWC cooling engine, in addition to checking the expansion tank, check the heat exchanger. The heat exchanger should have a small "pencil zinc" that screws into the top. If this is not checked regularly, the exchanger will go and you will need a new one. In my case, this was found in the survey. It was also found that when the exchanger went, it corroded the engine mount and messed up the prop shaft.
Do check the zinc in the heat exchanger and, when you buy the boat, have a few on hand.
My H34 is a 1983 and has a Westerbeke. However, in terms of what to look for in a FWC cooling engine, in addition to checking the expansion tank, check the heat exchanger. The heat exchanger should have a small "pencil zinc" that screws into the top. If this is not checked regularly, the exchanger will go and you will need a new one. In my case, this was found in the survey. It was also found that when the exchanger went, it corroded the engine mount and messed up the prop shaft.
Do check the zinc in the heat exchanger and, when you buy the boat, have a few on hand.