Correct spark plugs for 87 225 Looper

Blake0912

Petty Officer 1st Class
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Oct 31, 2010
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I just converted my 1987 225 johnson over to pre mix and did a seafoam decarb so I was going to replace the plugs. What spark plugs are best to use for this motor? Currently it has Champion QL78TC plugs in it. Thank you
 

Joe Reeves

Supreme Mariner
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Feb 24, 2002
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13,262
Re: Correct spark plugs for 87 225 Looper

Unless the recommended s/plug has been superseded up to the Champion QL78TC plugs and I'm not aware of the update..........

The original recommended spark plug is the Champion QL77JC4 plug, gapped at either the original recommended gap of .040 or the later recommended gap (late 1990's) of .030 . One gap or the other may provide improved performance at either idle or the higher rpms.... it varies from engine to engine for some reason.
 

Blake0912

Petty Officer 1st Class
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Oct 31, 2010
Messages
313
Re: Correct spark plugs for 87 225 Looper

Should I go with the original reccomended QL77JC4 plugs instead of the others? My idle has been a little rough I'm thinking the correct plugs could help.
 

Joe Reeves

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Joined
Feb 24, 2002
Messages
13,262
Re: Correct spark plugs for 87 225 Looper

Should I go with the original reccomended QL77JC4 plugs instead of the others? My idle has been a little rough I'm thinking the correct plugs could help.

I'd recommend going that route.
 
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