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82' johnson 115hp fouling plugs

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davek258

New member
Greetings. My 1982, 115hp Johnson is fouling all 4 plugs after a day or so use. Oil mixture is 50:1. Thick, sticky oil running down outside of engine case after use too. Compression is 110 on 3 of the cylinders and 95 on 1. Always seems to run a bit rough too but I'm guessing that could come from the low compression on one of the cylinders. Any thoughts?
 
Take the head off on the cylinder with that low compression.----You will find a blown head gasket or broken piston ring pieces embedded in the piston and cylinder head.---Motor needs serious work I believe.
 
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Wrong plugs
Wrong oil
Stuck open thermostat
Stuck open pressure control valve
Carb floats not set correctly
Is this somthing that just started?
 
This has been happening since I put the motor on my pontoon boat 2 yrs ago. It only gets used a few times a year. I just replaced both thermostats before the last outing and still have the issue. I will check to see that the correct plugs are used as well as the oil. I am not familiar with a pressure control valve and will research that as well as the carb floats. Thanks
 
I have no tach on the boat so I don't know what the full throttle RPM may be but I can tell you it's not as high as it should be. The plugs are fouling with heavy, gummy oil
 
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