1969 Johnson Supersea Horse 40 HP

Joined
Oct 19, 2011
Messages
65
Hey,

I recently cleaned the the carb and replaced the fuel pump because it was running weird. It was lugging when I had the throttle floored and it was running like crap. I gave it a test run and noticed that one of the cylinders was slow to fire as I reved the engine up. When running the engine with a dirty carb, does it have the potential to gum up the spark plugs? The spark plugs are new but I did run the engine a couple times with the dirty carb when it was running like crap.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1969 Johnson Supersea Horse 40 HP

Is the engine running on both cylinders?
Have you checked the spark, will it jump a 1/4" and is it bright blue.
 
Joined
Oct 19, 2011
Messages
65
Re: 1969 Johnson Supersea Horse 40 HP

how do I check the spark? Should i take the spark plugs out of the engine and leave them attached to the ignition and have somebody check to see if they are arching?
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1969 Johnson Supersea Horse 40 HP

You need to make sure the spark will jump 1/4". If you don't have an air gap tester, use a phillips head screw driver and insert it into the coil spring inside the boot and hold it 1/4" away from a head bolt while someone spins the engine over. Look for a nice blue spark.
 
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