Faulty heat gauge or ? 1988 V135

JohnWI

Seaman
Joined
Sep 14, 2011
Messages
73
She's new to me. Not overheating (via the warning horn) but the temp does rise to 3/4 on my dash gauge. Generally operates at the mid to 3/4 reading. I've tried my best to get in IR reading on the different areas of the heads and my readings have only been around 150. Both sides seem close, to 10*, difference. I've checked the thermostats on the stovetop for operation.

Is the temp sensor reading an area that's much deeper (toward the piston wall) than where my IR gun will read on the heads or are they quite close and my gauge's 3/4 really= 150*?

Who's done gauge changes and seen some improvement in their readings? My gas gauge only goes from about 1/8 (bone dry) to 3/4 (so full it sometimes spits out of the p-trap/vent). My speedo is very close to GPS but the trim gauge could also use some more span in it's readings during trim.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,241
The thermostats on that motor open at 143*F. The motor should run at idle somewhere around that temp. However, above idle the poppit valve takes over. It dumps water out the exhaust at 2000RPM or so, as water pressure dictates.

A temp gauge is not real accurate for those motors. A water pressure gauge for the waterpump is much more useful. Just monitor the PSI at idle and midrange, and it will tell you the motor is cool.
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,273
you seem ta be one of tha lucky ones with tha temp gauge reading!.. 150 is 'bout normal.. those type gauges can be all over tha place as for "position" of tha needle.. tha only way ta be sure of temp is with a gauge/water temp sensor.. trust tha warning buzzer more than tha gauge............. gas and speedo?.. lucky they both still work!.. trim is what it is.. you might be able ta adjust tha sensor but really doubt it plus those trim sensors are pretty scarce..

like chris says, get a water pressure gauge...........
 
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