compression

[juice71]

The compression on my Johnson 75hp super sea horse (1963) is down to 75-80 in all cylinders? My question is will my motor still run for another season. I think I should have at least 100 across the board. I am also only getting spark from 3 out of 4 plugs, could this just be down to bad wiring? Any input would be greatly appreciated. Thank you

 

[wilde1j]

Re: compression

I would try decarbonizing (OMC Engine Tune or NAPA Sea Foam) and see if the numbers improve. Get a shop manual to trouble shoot ignition.

 

[Droll]

Re: compression

If you got spark from 3 out of 4 plugs , I can only se 2 possible errors .<br />1: Bad plug , swich plugs .<br />2: Bad plug wire , try one other that you know is working .Messure from inside distributor . <br /><br />3: Look inside distributor , dirt ,cracks ,<br />4: Bad coil ( not likely ) .<br /><br />ok it become 4 points , but #1 or #2 in most likely .

 

[juice71]

Re: compression

Thanks for the quick response will try all mentioned.

 

[juice71]

Re: compression

how do I use the seafoam?

 

[OBJ]

Re: compression

Hi juice...<br /><br />Generally speaking, hook the engine up to ears for water, start the engine and let it come up to temp. You will need to idle the engine up a little to take the tuner. After the engine is at temp., start putting the seafoam or what ever your using into the carb throats. Use the whole can. Let the engine set as per instructions on the can. Restart and blow the stuff out.<br /><br />This is just a general instruction. The can should have directions on it.

 

[juice71]

Re: compression

thanks jim. I'm in Canada, does seafoam exist up here?