Engine Temperature Sensor

Does anyone know how I can go

Does anyone know how I can go about determining the exact sensor that needs to be replaced on my ford engine? I have a Searay w/an OMC800 outdrive driven by a ford engine. The mechanic said that my temp guage was not receiving a signal from the engine temp sensor - and he pointed to a small "thing" sticking out of the engine on the top. It looked like it had a signal wire and he tested that it was not working. Like my previous post ... I want to do this to learn something and save money. He wanted 150 to replce it ... chances are I will be able to buy one for thiry bucks.

"$150 is an eye gouge. If you

"$150 is an eye gouge. If you can disconnect a wire and ground it, you can test this gauge. If you have a wrench that fits the sender, you can replace it. Just don't overtighten it. Grounding the sensor wire to the motor withthe key on will make the gauge go to its max hot indication so you don't want to keep it grounded for too long. If the gauge moves, the wire and gauge are good- replace the sender with a standard Ford sensor of the right temperature.

If the gauge doesn't move, find the sensor wire on the gauge and connect that post to ground(the black wire on the gauge is a good place). If it still doesn't move, the gauge may be bad."

"Well you don't say what e

"Well you don't say what engine size or year but since it's an 800 I'm assuming an 8 cyl. This link will show an exploded view of the intake manifold. Item # 40 is the water temp sender.

http://www.dougrussell.com/partscatalog/volvo_omc/index.cfm?fuseaction=comp&grou p=116&GroupList=109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124"