Temperature gauge low when running

[Boating_Al]

Need a little help…I installed a temperature kit on mine 2001 135hp Johnson with one sending unit. When I’m idling the temperature reads fine, but when I take-off the temperature gauge goes to zeros. Installation was simple, no big deal. Where/What should I check for….<br /><br />thanks guys.

 

[R.Johnson]

Re: Temperature gauge low when running

When running at full throttle, the poppett valves are off of there seats allowing full water flow thru the engine, this will show a lower temp on the guage. At full throttle the engine need's maximum cooling. If you run an engine on muff's at idle the engine will be slightly hot to the touch. If you rev it up to open the valve's, you will feel the temperature drop.

 

[Boating_Al]

Re: Temperature gauge low when running

Thanks...can I install another sending unit on the other side of motor with out having to put a switch to control which side of the motor the gauge is reading.

 

[papa_Lazerous]

Re: Temperature gauge low when running

in short no you cant have 2 sender unts on one gauge.<br /><br />I would say aslong as your engine has a good stat and the impeller is good and you fluch it after use if you use it in the salt I wouldnt worry too much about heat. At the end of the day your gauge is reading low under load. If there is a problem it will rise

 

[Boating_Al]

Re: Temperature gauge low when running

Thanks again...since I already have the two sending units I guest i'll put a small switch to control the P/S side of motor. I read that before putting in the sending unit it's good to put some thermal compound in the hole on the block where the sending unit goes in...do I really need to do this?

 

[angus63]

Re: Temperature gauge low when running

The thermal grease will give you a quicker response time to changes in temp, but only about 30 seconds before any lube will soak up the temp and give you an accurate response. If you use a graphite compound grease, you will have a slightly more "real time" reading. Your warning horn will sound before you'll notice the difference anyway. Really, how often are you eyeing the gauge anyway? Temp gauge is nice, warning horn is critical.<br />Good luck