Temp. Sending Unit

[vulcandar]

I was wondering if I could hook up a Temperature guage to my boat?. I have a 20' pontoon boat with a 2002 60hp. 2 stroke mercury bigfoot. Can anyone tell me if theres a spot on the engine to screw in a sending unit? The # on the motor is OT437387.

Thanks you, Dave

 

[Silvertip]

Re: Temp. Sending Unit

It doesn't matter if there is a water jacket port or not. Two types of sending units are available. One is a contact type (actually a cylinder head temp style sender, and the other is a threaded style that screws into the water jacket. My 75 HP has a port but off-hand I don't know if the 60 does. Here are examples of both types.

Here is the installation on my 75 HP Merc.

If you are buying a gauge, make sure you get one that reads 60 on the low end of the scale. Outboards run cool so a gauge that reads 100 or 120 on the low end will hardly ever move. Some gauges are also calibrate C - N - H (cold, normal, hot) which is really not much use as you still have no idea what the actual temp is. 60 degree gauges are getting hard to come buy.

 

[MercGuy]

Re: Temp. Sending Unit

Silvertip,

Interesting comment about the 60 Degree gage. My 1998 115 runs around 140 degrees at idle, then quickly cools down to the bottom peg of my temp gage (100 Degrees) when I put the hammer down.

I've assumed that this is normal, because the popitt valve opens when water pressure increases with engine RPM and then bypasses the thermostat. Am I correct about this ?

Thanks !

 

[Silvertip]

Re: Temp. Sending Unit

You are correct?

 

[whistlepigcam]

Re: Temp. Sending Unit

I recently had a temp guage installed. 100 degree. Could not get a reading until the hose muffs fell off the motor. The fellow who installed it said basically that the water flow sas so good it kept the temp low.

I have found the afore-mentioned guage 60-220. Faria Gauge Kit far12819
Less than 30 bucks.

Contemplating ordering it next week. I already have the wiring in place. Wondering if this would be a good thing to do.

Any thoughts or suggestions would be appreciated.