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SUBJECT: # 17232: 4.3 mercruiser I/O
Submitted by Navy Dude in Puerto Rico (205.68.92.66) from OTHER on 9/11/2000 10:45:00 AM
Hope one of you smart people out there can help me here, A friend recently replaced a 4.3L Mercruiser I/O engine with an automobile engine, same size 4.3L V6. But he has been having this problem when he runs for a while at around 4000 rpm. When his temp reaches about 200 he starts to lose power and continues to lose power until he finally gives up backs off and sits for a while running at idle. Once the engine cools to about 180 he can take off again. I was guessing it may have been a leaking head gasket as the engine heated up, but I could not find anything in his tech manual about retorquing the heads after a break in period so I am reluctant to try it. Any suggestions????? Thanks...
- 9/11/2000 1:16:00 PM
Submitted by
Billybob (208.221.183.153) from CONNECTICUT says What's he got for a t-stat?
Is he running an auto thermostat in there? The car t-stats can be 180, or 195 as I recall, and the marine are 140 - first thing to do is check that he is running the right t-stat.
- 9/11/2000 4:07:00 PM
Submitted by
Local Motion (152.163.213.183) from NEW YORK says auto motor....
NavyDude, as Billybob said the stat for a raw water cooled motor is 140-something and for fresh water cooling it is about 165.Hope your buddy used marine head gaskets, cam and water pump.
With the right cam it should turn 4400 to 4800 rpms.
Sometimes the circ pump on the motor of non-marine pumps have blades that are directional. The marine pumps have straight blades so they can be used for counter rotating motors.