Temp guage cuts out

[bbach]

I have a temp guage on a Johnson 120 hp. Seems to work fine when I leave the dock and idle out to the lake but cuts out shortly after that. Any idea how to toubleshoot this? I'm guessing it might be getting too much voltage under higher RPMs. How can I check this? Thanks.

 

[DJ]

Re: Temp guage cuts out

I'm guessing it might be getting too much voltage under higher RPMs. How can I check this?

Easy. Put a voltmeter across the battery terminals.<br /><br />

Seems to work fine when I leave the dock and idle out to the lake but cuts out shortly after that.

If you truly have a "temp" guage, most of them work by a probe touching the head(s). As the engine heats up, metal expansion may be pushing the probe tip away from the head(s).

 

[bbach]

Re: Temp guage cuts out

Thanks DJ. I'll take a closer look at the sensor and get out the multi-meter. I assumed the sensor would be bolted to the head but I'll have a look at how it attaches. What should I be seeing for a max voltage across the battery terminals?<br /><br />-- Bud