Normal Temp

[wcmaness]

I have a 1985 Mercury XR2 150. I just changed the water pump impeller, and at the same time decided to hook up the temperature gauge that's been disconnected for years. I noticed that the guage goes up to about 1/4 past the 1/2 way mark when running. There are not temp numbers on the guage, just lines. My question is - what is the normal temp supposed to be? is this running hot, or normal?

 

[KenMcG]

Re: Normal Temp

You cannot trust the indication of cheap, old, weathered temperature gauges and also taking into account the possibility of corroded connections and parts that have been baked and frozen either by summer and winter etc.

I would do this: with the engine fully warmed up and at normal operating temperature, take a spray bottle and spray a mist of water on the head cover around the spark plugs. If the water does not immediately steam off, I think your operating temperature is well within normal limits.

I added an aftermarket temp sensor and gauge to and engine and the gauge read from 100 to 240 degrees. It never went above 110 degrees.

Ken

 

[KenMcG]

Re: Normal Temp

Because a boat engine has an unlimited supply of cool water, I think they run around 140 to 160 degrees at most, or the temperature of coffee. At full temperature, you could probably put a hand on the engine for 2 or 3 seconds before it is too hot for your hand.