Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

[BeaterSkeeter]

I have a Johnson 115 V4 - I was told it was an 84 - the motor has a sticker that says use champion UL77V plugs which corresponds to an '85 from the spark plug lists I looked at.
http://www.iboats.com/Johnson-Champ...6300814--session_id.720120536--view_id.669920
The motor currently has the UL77V plugs in it. Champion describes this as a race plug with unique operating characteristics and requirements. Also says it's prone to carbon fouling.
http://www.championsparkplugs.com/more_info.asp?AAIA=&pid=4436

The other plug listed for this motor for 75-84 is a champion QL77JC4, which is a resistor plug with a standard adjustable gap.
http://www.championsparkplugs.com/more_info.asp?AAIA=&pid=8807

Are these plugs interchangeable since they are in the same heat range? The electrode on the standard plug can't hit the top of the piston domes on the special V-4 pistons, can it? That would seem like an awfully narrow squish band if that were the case. Should I just set it up with the same .30 gap as all the others? I'm just curious as to why the only plug suggested for use in this motor would be a race plug. To me it seems these plugs should be interchangeable but I figure why not ask here and see if someone has the knowledge to share. Thanks!

 

[Daviet]

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Says they will interchange,#34 below. Never new the surface gap plugs were racing plugs, always replaced them with the center electrode type.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[Jlawsen]

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

The two strokes that I deal with actually do quite well on surface gap plugs. I'd stick with them if it were me.

 

[TrueNorthist]

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

I prefer the surface gap plugs as they seem to work better for my 6hp, both for trolling and WOT. I do not notice any carbon problems, but I routinely pull the plugs after each trip out and clean them with carb and choke spray cleaner. Makes a plug last a lot longer. And you will not damage the piston using adjustable gap plugs as long as they have the correct thread reach.

 

[V153]

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

It's rumored that the surface gap plugs are better for top end. Though most of the go fast OMC boys I know run NGK fine wire Irridiums.

 

[TrueNorthist]

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

Re: Are Surface-Gap Sparks Plugs & Standard-Gap Plugs Interchangeable on a 115HP V4?

The OP might want to read here. I had noticed a decrease in "sneezing" too after switching to surface gap plugs but was afraid to say that without some sort of proof. It looks like the increased air-gap acts as increased resistance which in turn gives a better spark on CD ignitions. I think I will try the NGK resistor types next time and see if that is even better. I am running Champion L76V plugs right now and NGK is usually a better plug but who knows...