Spark Plug replacement!

[ostiano10]

I have a 1987 2 Stroke 90 HP Johnson outboard that I want to change the spark plugs on. I was just wondering if anyone could give a possible tutorial of the steps to complete this task. I have replaced on cars before, but not on a marine engine. Also if any tips as to where to buy the plugs, i.e are there special marine made plugs.

Thanks!

 

[ostiano10]

If I can also add with a 2 stroke does that stand for 2 cylinders so there would be 2 plugs?

 

[interalian]

Your 90 is a 4 cylinder, therefore 4 sparkplugs. Nothing magical about an outboard vs an auto for changing them. Look up your year on Champion's site and select the plug from there.

 

[Chris1956]

Plugs for outboards are sometimes sold at auto parts places, for a discount over marine stores. There are also specialty spark plugs for OBs that have a stainless steel plug shell. The balance of the plug is the same. I usually get the regular plugs for $2.50 or so, and toss them out when they get rusty (4 years or so). Some marine plugs are surface gap. Just install them. Your motor probably runs a gap-style plug. Check the gap before installation. Usually Johnny motors want a .030 gap.

 

[jrs_diesel]

Yep pretty simple and straight forward. Make sure the gaps are all set correctly (.030 or .035 if I remember correctly).

The clarify your other question, 2 stroke means the cylinder fires once every revolution, 2 strokes of the piston.

 

[ostiano10]

Thanks you very much for the replies! Ended up swapping them today, posted another question about issues with low rpm if you could take a look it would be much appreciated!