trobbins0000
Cadet
- Joined
- Jan 12, 2010
- Messages
- 6
I have a 1990 Merc 4.3 engine.
The temp gauge is not working. I tested the gauge by grounding the sending lug, and the gauge does not "pin", it just moves slightly hotter.
So my first problem is a bad guage, can I use an auto gauge, or does it need to be marine.
I also checked the temp sender in the thermostat housing. When I measure the resistance between the outside of the sender (the threads that go into the thermo housing) and a good engine ground, I get about 900 ohms. Same between the thermo housing and the engine ground. I would expect the thermo housing to be at ground.
The 2 bolts that hold the thermo housing are at ground, but the housing itself is not.
Starting at the intake man, there is a gasket, then the housing, then another gasket, then the cover, which the bolts go through. How does the thermo housing get grounded? It is isolated by 2 gaskets, so the bolts won't provide the ground. Unless they are relying on the bolts going through the housing to ground it.
Thanks,
Tim
The temp gauge is not working. I tested the gauge by grounding the sending lug, and the gauge does not "pin", it just moves slightly hotter.
So my first problem is a bad guage, can I use an auto gauge, or does it need to be marine.
I also checked the temp sender in the thermostat housing. When I measure the resistance between the outside of the sender (the threads that go into the thermo housing) and a good engine ground, I get about 900 ohms. Same between the thermo housing and the engine ground. I would expect the thermo housing to be at ground.
The 2 bolts that hold the thermo housing are at ground, but the housing itself is not.
Starting at the intake man, there is a gasket, then the housing, then another gasket, then the cover, which the bolts go through. How does the thermo housing get grounded? It is isolated by 2 gaskets, so the bolts won't provide the ground. Unless they are relying on the bolts going through the housing to ground it.
Thanks,
Tim