Honda BF50 high temp light

[Canuk]

The high temp indicator light on my 1999 Honda BF50 remote has been lighting up shortly after the engine is started. It was first noticed when returning to dock after a 3 hour trip. The water check flow was OK and the water peeing out was definitely warmer than its source. I took the cover off and the block/head did not feel overheated (as far as I know) and the oil temp/colour/level was OK. According to the manual when a high temp occurs "the light will come on, an audible alarm will sound and the engine revs are limited to idle" in my case its only the light. Is there a way to check the temp indicator signal? Does the thermostat fail closed? What is the actual normal running temp and high temp setting? I use it on a small lake for fishing and 95% of its run time is at idle (trolling) with 5 minute bursts at 3/4 throttle to get to the next hole. Any help in this matter would be appreciated greatly.

 

[Canuk]

Re: Honda BF50 high temp light

UPDATE!<br /><br />Tested thermostat-opens at 162 deg F-ok.<br />Head temp checked with raytek after 10 min idle bottom cyl @ 120, middle @ 140, top @ 160.<br />Telltale flow temp 16-20 deg hotter than lake.<br />Removed red lead from temp switch and faint red light stayed on.<br />Grounded red lead to temp switch, indicator light went from dim to bright but no buzzer.<br />tested continuity of temp switch-open circuit-ok.<br /><br />Could it just be a ground fault????

 

[hondon]

Re: Honda BF50 high temp light

Good leg work.Yes you likely have a short in that circuit and it is probably at the helm especially if you have a side mount control that has been converted from one handle side to the other to accomodate your boat.Like most side mount controls the wiring is packed very tightly and pinching a wire is not uncommon.Chafing can also occur anywhere you are rubbing anything.Do an ohm check between the sender wire and a good ground.Circuit should be open.