1976 SeaRay Mercruiser overheating

T

tmatouse

Recruit
Joined
May 17, 2010
Messages
1
I have a 1976 Mercruiser with a Ford 351ci V-8 that over heats when I try to go on plane 2,500rpm plus, it will run all day at lower rpm's. Have replaced the impeller in the outdrive, replaced the thermostat and water pump, checked the timing. This is not a slow temp. rise it jumps up very fast. Any ideas where to look next ?
 
zbnutcase

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: 1976 SeaRay Mercruiser overheating

Exhaust manifolds and/or risers.
 
H

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: 1976 SeaRay Mercruiser overheating

You could try just replacing the temp sensor to see if you have a sensor giving a faulty reading. An infrared temp gun could help verify the engine temp in comparison to the temp gauge.
 
Q

Quadruplecccc

Petty Officer 2nd Class
Joined
Apr 3, 2006
Messages
133
Re: 1976 SeaRay Mercruiser overheating

Had a very similar problem. Turned out to be a short from the light in the guage. A strand of wire was touching the hot lead of the light to ground. Temp would spike to 200* within 3 min. Looked at all the big stuff first as you have and could not come up with anything that was logical. Try wiring in a guage back at the motor and see if things change. I have the same motor so, Hope this helps. chuck
 
You must log in or register to reply here.
Top