GT-40 temperature sending unit?

[jslow68]

I have a 2000 Ski Nautique. It was stalling out and the check engine light was on. Oil pressure was fine and also the engine temp. After some trial and error, I figured out the tmeperature sending unit on the top manifold was making the check engine come one. I was also under the assumption that this sending unit would make the boat go into limp mode. When I disconnect the wires to the sending unit, it would make the check engine light go out.

I replaced it with a cheaper Sierra sending unit and I still have the same problem. The check engine light is on, but when I disconnect the wires to it, the light goes out.

Did I get a bad sensor or is the cheaper version not compatialbe? Or do I have a totally different problem?

[jslow68]

After some research, I found that the water temp sending unit is wired to the oil pressure switch which also turns on the check money light. And puts the boat into limp mode. After changing the the oil pressure switch, (not the oil sending unit) the light was off and ran fine.