Engine Temps

[Time Flies]

I have a 25" Mako, with a 1990 Johnson 225 my engine has a temp guage, flat out running my temp is 175 deg is that high, it doesn't seem to get any hotter, I think that there might be a guage problem, any thoughts?

[classic73mako]

When your running flat out the two thermostats on the motor heads open up an allow the water pump to pump as much cooling water as possible to pass directly into the heads and the rest of the motor. I can't remember what tempature a 225 Johnson uses for thermostats but for most motors it's usually around 160 to 175 degrees (cars run a lot hotter i.e. 200 because of the antifreez and closed system). 175 degrees dosen't sound bad (if the gage is OK) when you remember that she's making 225 HP in that little space under the motor hood. I doubt seriously that your gage is off - they are real simple and usually don't fail. I depend more on my water pressure gage that the temp gage as if you have water pressure you know that your getting cooling water from the water pump through the engine.

Hope this helps -

Mike

[Time Flies]

I do not have a water pressure guage, I have just been looking at the pisser on the back of the engine, that it has a good stream of water. Is that smething that I should put in the panel and where would it tie into at.

[classic73mako]

There is a pressure sensor with a small plastic hose that would run from your motor to the pressure gage that is mounted in the dash. The water pressure sensor is screwed into one of the plugged openings (designed for this reason) on the top or side of your either of your motor's heads. The gage will tell you what amount of water (or) pressure the water pump is putting out which is forcing the cooling water thorugh the motor. With 2 cycle motors you assume that if the waterpump is working that you motor is being cooled OK. Should you get one?? That is up to you. I look at it this way - If you don't have any water pressure you don't have any motor cooling - i/e. the pisser stops and that's not good. Me, I like overkill on anyting that needs to get me back from 50 miles south of Montauk Point NY.

Mike

[elwilliams13]

I got the same engine and it runs right around there. OMC used a vernatherm in that model engine. It goes attached to a diaphragm inside your thermostat housing. It has a opening temp of 140F etched on the metal part of the thermostat.

[Time Flies]

well the temp problem makes me feel better, when I am trolling the engine runs cool, thanks for the input guys and I will look into a pressure guage. Caught 10 mahi mahi yesterday!