20HP Johnson Spark plugs?

[SteveRay]

My dad has a 20 HP JOhnson outboard iwth the following info:
Model Number: J20CRLCOS
Serial Number: E6063402
My question is what plugs are recommended and also what gap to set them at.
Any other recommendations besides changing gear lube/water pump? Basic tune up info? Would this engine benefit from a good decarbing with Seafoam?​

Thanks guys​

 

[Basher]

Re: 20HP Johnson plugs?

Re: 20HP Johnson plugs?

SteveRay

J= Johnson

20= Horsepower

C= Counter Rotation
R= Rope Start

L= 20" Transom

C= 8
O= 5

S= Model Run #

So what you have is a 1985 Johnson 20 HP. Run it on 50:1 fuel mixture, use Champion plugs #QL77JC4 gapped at .030". Yes seafoam would not hurt.

Basher

 

[tashasdaddy]

Re: 20HP Johnson plugs?

Re: 20HP Johnson plugs?

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.