125hp Running Hot

ryan04

Petty Officer 1st Class
Joined
Jan 26, 2005
Messages
212
Hey guys, quick question. I have a 1972 125hp johnson, I threw carb kits on both carbs the other day and popped them back on the engine. I started the engine and it fired up and idled beautifully again, the only thing is it was running hot. I had the muffs on it and there was water peeing out the usual spots, as well as the two exhaust ports on the back which I never have observed before,but the water was hot, then I felt the cylender heads and they started to get quite warm then hot at last. All this took place in about 5 min after starting it, so my questions are, where do I start looking. I don't know if I should buy an impeller kit and a new thermostat or what. What should I start looking for. thanks alot.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 125hp Running Hot

Did your hot horn go off? Your engine does not have the telltale, so hold your hand behind the two exhaust relief ports at the back of the engine midsection. When warmed up, the thermostat will open and your hand will start to get wet from water droplets. Usually this is a good sign the cooling system is working. Sounds like you did this and it is still overheating.....how long since you replaced the impeller? If you don't know, replace it. Check the shape of the housing (for an overheat) and the fit between the two water tubes. I would also have a look inside the thermostat housing. I would replace the vernatherm and also look at the check valve/spring. Possible that you have debris in the housing..
 
Top