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1977 Johnson head gasket

N

nytebyte

Regular Contributor
I picked up this motor and was told it had problems running. First checked compression and was 90 and 92. Figure it should run with that and checked spark with tester and that would make the jump so all good so far. I put it in my water barrel and got it started and was pumping good but had to choke it to keep it running so did the carb and all was good with it now. Put it back in the barrel and same thing so decided to pull the plugs and they were wet with greyish water and kind of foamy. Figured head gasket and pulled the head and the gasket to my eyes looked fine and could not see where it would have been leaking so my question is there any place else water could be getting into the cylinders? Was told it was fresh mixed gas about 2 weeks old when I picked up the motor so figured it was fine. If no place else for water to get in I feel I may have made a mistake using that fuel.
 
Model # of this motor?--Lower crankshaft seal is one place where water can get it..----Gaskets on the exhaust manifold are the most likely place where water leaks into a cylinder.
 
Use a piece of glass and emery to resurface the cylinder head.----All 1977 cylinder heads are warped !-----just finished a 1981 15 HP and it was warped like all of them.
 
After letting the head gasket set a bit I can see where water may have got in. Going to go ahead and get new one and will do thermostat as long as the powerhead is off. Cant see anywhere else looks to have been leaking in. Will be sure to get the head flat!
 
Dont forget to use a LITTLE nickel Anti Seize on the cleaned threads of head bolts....why? There is a very thin zinc coating that wears off when bolts have been in and out a couple times and cleaned. If you dont take care to do this, they will oxidize and can be very difficult to remove years down the road. In my repairs, every bolt and screw gets this treatment. Water pump bolts, thermostat, lower unit bolts....etc....and yes they stay tight. The next mechanic will always appreciate this as well. Shops rarely do this....most are in it against the clock, the boss, and for the money.
 
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