Confused about what Spark Plugs to use.

[Xeenan]

My 15R75C says on the transom bracket to use Champion L7J plugs, but, in my Clymer manuel it says to use Champion UL81C and im finding that same recomendation on other web sites.

So which do I use and is there a difference between the two???

 

[Joe Reeves]

Re: Confused about what Spark Plugs to use.

The Champion L7J was the original recommended sprk plug BUT has been upgraded to the Champion UL81C. I assume you're sure about the "C" designation? I recall that the number was UL81J...(J), BUT if you're sure of the "C" and you can find that plug, use it.

 

[Xeenan]

Re: Confused about what Spark Plugs to use.

ok well I bought 2 L77JC4 plugs yesterday at autozone. I assume it wont hurt to use the older recommended plugs??

 

[F_R]

Re: Confused about what Spark Plugs to use.

L77JC4 is nowhere near the same thing as the two previously mentioned plugs. It is a super cold plug. It might run 10 minutes on them before they foul.

You may be interested (?) in knowing that that motor was h--- on plugs. Even the mfr couldn't make them run on certain boats. That's why there is disagreement on plug types.

The "U" in UL means it has an internal booster gap. That was an effort to make them fire even though fouled. The "J" meant two stroke plug. No longer made. Replaced by "C" which means copper electrode. The copper does nothing to prevent fouling.

 

[Xeenan]

Re: Confused about what Spark Plugs to use.

Ya I think im going to take them back and exchange them. I just looked up the plugs on Champions web site and it does say to use UL81C.

http://www.championsparkplugs.com/results_appOther.asp?otherMotiveID=12445&mfid=2

It doesnt say that it is a Marine Plug but a racing series plug. On the package of the L77JC4 it says marine.