1978 Johnson 140 plugs (air gap or conventional?)

Ranger 330V

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okay my 78 johnson 140 has conventional plugs...my new OMC manual I got says it should have air gap plugs. What are you guys running and what do you prefer? I figure a hotter spark or at least a bigger spark out of the air gap...thats what I'm running in my 1150 merc and have had good luck with them...champions...all opionions welcome! thanks!
 

tashasdaddy

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Re: 1978 Johnson 140 plugs (air gap or conventional?)

the air gap are recommended if you do a lot of high speed running. the conventional are recommended if you do a lot of trolling. i like to open the .005 more than recommended for trolling, cuts down on fouling.
 

F_R

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Re: 1978 Johnson 140 plugs (air gap or conventional?)

I hate surface (air) gap plugs. Unless there is danger of pre-ignition or there is a lot of loose flaking-off carbon in the cylinders, I see no use for them. Conventional plugs will run fast or slow. Surface gaps require excellent ignition.
 

MikDee

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Re: 1978 Johnson 140 plugs (air gap or conventional?)

I hate surface (air) gap plugs. Unless there is danger of pre-ignition or there is a lot of loose flaking-off carbon in the cylinders, I see no use for them. Conventional plugs will run fast or slow. Surface gaps require excellent ignition.

This is my opinion of them also, after having experience with them in the past. Apparently I have no choice, as they are the only style plugs listed for my Force 125hp, and I think all Force outboards, I think it might be a piston clearance issue?
 

Ranger 330V

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Re: 1978 Johnson 140 plugs (air gap or conventional?)

thats kind of what I was wondering about...I know it does take alot of juice to fire those air gap plugs...do you think air gaps are harder on ignitions?? I bass fish in lakes so I won't do just to terribly large amount of trolling...more of starting, running, stopping kinda thing. Maybe an occasional tube or knee board in the summer. This is an engine that has set up for a while so maybe a good idea to run air gaps until I get all the decarbing done then switch to conventional?? Seems like this may be one of those 6 one way half a dozen another things...comes down to personal preference. Thank you guys, maybe some more will chime in on what they think about them.

Tasha...I'll have to give it to you....Florida has been looking PRETTY salty here lately...T-Bo is a force to be reckoned with...I'm in Arkansas and have to support my hogs..its just sad that we have two of the best running backs in the nation and D-MAC probably won't even get much of glance this year because the rest of the team isn't doing well. For heisman I mean. Nutt does great with running backs...but I'm REALLY tired of walk on QBs and lousy receivers...everyone knows what we are going to do EVERYTIME...lol...sorry I'll get off my soap box now!
 
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