Trojan Boat Forum

I have a 1985 Trohan 10 Meter with crusader 454's. The engine water temp gauge on the starboard engine stopped working. I verified the gauge iss good by swapping it with the Port engine gauge and the one I thought was faulty works fine on the other engine. So then i replaced the water temp sending unit. Still no luck. I;m not sure where to go from here. Any suggestions? Good ones preferred

did you swwap the senders? wire?

Make sure you got a sender for a gage ( not a light) ground the wire at the sender and see if it reads

If your thermostat is open, the temperature will probably never climb off of cold while idling. Are you looking at the gauge while you're warming up or running the boat?

Otherwise, as Paul says, ground the temp sender unit and see if the gauge moves. Also...be sure you're not confusing the temp sending unit with the alarm sending unit.

Thanks for all the advice. I have already tried everything except grounding the wire. I am almost convinced the wire is the problem as I have already eliminated most other options. Thanks.

OK I've been back to the marina and here's what I found. If I ground the sender wire the gauge pegs hot. Si I assume that means the wire is good. So here's where I am. The gauge works, the wire is good, and the sender is new. So what's left? I'm starting to think maybe the thermostat is just stuck open and the engine doesn't heat up enough to move the gauge. Any other suggestions?

Get one of those temp guns and check the temp to confirm if the thermostst is frozen open.

The engine is running cool or you have a bad or wrong sender

prowlersfish wrote:The engine is running cool or you have a bad or wrong sender

I noticed my boat ( raw water cooled ) did not get over 120 this weekend.

from what you described in your first explanation, and keeping in mind that your engine is coming up to operating temperature ,seems your wiring is at fault. if you bring the gauge and hook it up directly to the sender at the engine, check it there to confirm its operation, there should be no more than two wires, one from the sender , and one to ground. If there is another, its probably for the illumination and is not needed for test purposes. if all works, its the wires, and replace them both. One wire goes to the sender, and the other goes to a post on the back of the gauge that is usually marked with an S the other of course goes to ground.
This is a typical installation of course you may have variations but not likely. the system is quite simple and you should resolve it easily. Of course if your engine is not warming up , that is a seperate issue and the thermostadt could be an issue.

If you cant resolve it with this info, feel free to call me anytime
201 741 4697 as I do this stuff for a living

savanahrae wrote:I have a 1985 Trohan 10 Meter with crusader 454's. The engine water temp gauge on the starboard engine stopped working. I verified the gauge iss good by swapping it with the Port engine gauge and the one I thought was faulty works fine on the other engine. So then i replaced the water temp sending unit. Still no luck. I;m not sure where to go from here. Any suggestions? Good ones preferred

Did you try running and testing current in wire. sometimes a break is the problem.