1982 7.5 cooling system

[steely51]

I just replaced the water pump on my &.5 merc. all passage ways are clear. the external temp on the thermostat housing and exhaust cover will cause you to move your hand after a while and the telltale stream is quite hot all the time if i put my hand under it up close to the motor. Is this normal?
I never paid much attention to it before, but I can't remember the telltale stream being quite this warm.

 

[albertaborn]

Re: 1982 7.5 cooling system

i have the same motor but have had nothing but problems with the cooling. what your describing should like an improvement to my motor.when u had the lower end off did u push air or water up the tube to see if its clear? im asking cause i have my own question about why it seems like my motor lets more water out the releifs then the pee hole

 

[Bubbles Up]

Re: 1982 7.5 cooling system

Hello,

Another 7.5 not cooling there is a shock. I have 79 Merc 7.5 that had cooling issues. Here is what I have had done to mine now it cools nicely.I had the water pump done as mine dried out from age as this motor sat for a few years.I launched the boat and went for a rip a short while later at trolling speed the water has quite hot,I called the place back that did the work the said to bring it back and they changed the grommet that the water tube goes into. A few days later back to the lake go for a ride and the water is luke warm enough heat to wash your hands under at speed.While trolling I would get sparatic dribbles out the pee hole. and nothing when I neutraled the motor. I took it into another place and they said that the exhaust reliefs were blocked.Needless to say with the help from here and a couple of websites,I pulled the exhaust plate off and it was plugged solid. I used a pneumatic de-scaler to break up the carbon deposits on the plate and the block side.Drilled out a couple of broken bolts,re tapped the threads.New gaskets and a tank test at my buddies place and the thing pees at idle in neutral like me after a 12 pack.
There was quite a bit of carbon/sludge flowing throughout the block and cooling I pulled the line to the pee hole and let it run onto the grass for about 10 minutes. I put the line back on and in the test tank at idle it peed and at troll it peed~ I have a feeling that at full speed I'm going to have a pressure washer!

I can dig thru my bills and come up with the part numbers of all the cooling related stuff,grommets ,gaskets,etc.