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MERCRUISER 165 HPRUNNING HOT AT IDLE

J

JAMES CRUMPLER

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"Hi Boaters!
I just purchased


"Hi Boaters!
I just purchased a 1987 Regal with the Merc 165 (Ford 224)engine. We took it out yesterday - it was very hot here in the south (98 degrees). When at idle, the temp quickly ran up - so hot that when we cut the engine, we had to let it cool down before the starter would even start it. If we ran it wide open - temp would come back down. As it cooled down last night, the temp stayed fine - running or idling. Any help would be appreciated."
 
""Merc 165 (Ford 224&#

""Merc 165 (Ford 224)engine"
165 was the GM inline 6, could you mean the "inline alum. block,fwc 4 cyl.commonly called the 470/488. has the impeller been chanbed in the lower unit?"
 
The 224 3.7 4-cylinder is also

The 224 3.7 4-cylinder is also called a 165 in some instances. It isn't a Ford engine - it is an aluminum block that Mercruiser cast and put a Ford head on. It has a closed cooling system with a heat exchanger. Check to see that your coolant level is up and thermostat is opening. Your fresh water impeller circulates water through the other side of the heat exchanger - not through the engine.
 
"Mike,
You're correct. I


"Mike,
You're correct. It is a 4 cyl, 165 hp Mercruiser. My husband is a GM Mechanic (23 years)so it's a joke with us that he bought a boat with a Ford in it! The fellow we purchased it from was not really the owner of the boat to begin with. He purchased it and did some fixing on it and just resold it. He put an impeller on it and resealed the waterpump so we're guessing that it was having cooling problems all along. It does have a heat exchanger as you mentioned. When it ran hot, it started blowing antifreeze out the cap on the tank and the resevoir was also running over.
We going to replace the thermostat this week and see if that helps. We're also thinking maybe the exchange is blocked. Is there anything you can do to check that without dismantling it?
Thanks!"
 
"If you are blowing coolant ou

"If you are blowing coolant out of the reservoir, you probably have a bad exhaust riser gasket (between the exhaust manifold and riser - 4 bolts). It isn't unususal to see one go bad and it is a cheap and easy part to replace. As far as the exchanger, you could pull the fresh water lines and put that side under pressure to see if it blows through into the other side. If someone didn't winterize properly, it could have cracked something inside. The 4" heat exchangers do a much better job than the 3" also. I'd lean toward the riser gasket though."
 
"Are you sure it's not a 4

"Are you sure it's not a 470 model? That was a 170HP 4 cylinder. Anyway,you may want to remove the water line from the water pump inlet side of the heat exchanger,start it and check for water flow. They may have not installed the pump right or the water tube could be blocked. In any case at least you can rule out the sea water pump.

Good luck"
 
"The 470 is a 3.7 litre - 224

"The 470 is a 3.7 litre - 224 c.i.d. Mercruiser block. The same aluminum 4 cylinder block has been sold under many variations: 165, 170, 190, 470, 485 and 488.
Many people get the two 165's confused - there is a 4 and 6 cylinder Mercruiser engine called a 165."
 
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