spark plug gap

[scully222]

I have a78 Johnson 85 HP and I am going to replace spark plugs. What is correct gap? I looked at a service manual Clymer and it says gap at .040 and then went to website boatsetup.com and it says .030.

 

[ezeke]

Re: spark plug gap

The boatsetup.com chart is up to date as of 2005, I believe. Check the edition on your Clymer Manual If it is the 7th edition the chart has not been updated since 1991, I understand.​

 

[bigbob_FTW]

Re: spark plug gap

I have a78 Johnson 85 HP and I am going to replace spark plugs. What is correct gap? I looked at a service manual Clymer and it says gap at .040 and then went to website boatsetup.com and it says .030.

Should be .030 (.040 if you troll a lot or for extended low speed operation)