Temperature guage only read 100 degrees??

[gss036]

My temperature guage only reads about 100 degrees, yet the water coming out of the telltale hole feels to be about 130-140 degrees(have not checked it w/a thermometer). How is the best way to check the guage to see if it working properly?<br />I was worried about the water stream because there is not a lot of pressure there, but a full steady stream after the flow begins on warm up.

 

[Spidybot]

Re: Temperature guage only read 100 degrees??

Hi Gary,<br /><br />Tell us a little more about your motor: Make & model, year, history of use.<br /><br />The tell tale stream may be affected by the thermostat which would explain the stronger tale when warm.<br /><br />If you check the tell tale temp with a standard thermometer you'll know the relation between actual and gauge reading.<br /><br />For comparison my 4-cyl 115hp never gets more than 130 - less when cruising, more when idling around.

 

[gss036]

Re: Temperature guage only read 100 degrees??

I talked with my mechanic today. Since it has been 3 years on the old pump and head gaskets, he is suggesting a change of both. Said that Mercury recomends annual/ semi-annual at the most. So I will take it to the shop this week and have it done.<br />The motor is a 1989 200 hp and has about 1200 hours on it. I have only put 100 hours over the last 3 years and that is because of our CRAZY salmon fishing rules here in Washington. We are only open about 6 months out of the year if we are lucky.<br />I asked about the small numbers of hours and he time is the key since the impellers are rubber and tend to dry out and get brittle. Said I should have about 22 lbs pressure at full throttle. I don't have a pressure guage so don't know what the pressure is. Definately not overheating though.