Original spark plugs number? VWB 52119 B

[sentinel]

This 15 Hp. 1981 Chrysler has mixed plugs...... not good mixing heat ranges! Any one know the ORIGINAL champion plug type that Chrysler put in their 15 HP outboards that year?
I suspect either a CJ8 or an old RJ19LM. Both are Champions. Thanks.

 

[roscoe]

Re: Original spark plugs number? VWB 52119 B

Don't know what the original was, but sparkplugs.com now list a Champion 5933 for that motor.

They list Autolite 425 and 2656 as equivalent plugs.
Also the NGK BR6HS.

 

[sentinel]

Re: Original spark plugs number? VWB 52119 B

Unfortunately, little info is available or can be verified on some of those plugs. What I am finding is a variance of 3 heat ranges, 6 to 9.

I am sure now the RJ19LM is not the original plug. Heat range is way too high. That plug probably came from a lawn mower and is at the top of the heat range spectrum. Additionally, if that plug were in the lower cylinder it would be very difficult to extract without a special wrench fitted for the cowling case.

This would bring me back to the small CJ8 plug which is in the mid portion of the heat range. But that small physical size plug on a 15 HP two cylinder engine does not set too well with my sense of balanced power.

Looks like I will have to start with a mid range 8 plug at my altitude, ambient temperatures, and my normal motor high and low RPM cruising under boat load to do a color and wet check.....

Wish I had original Chrysler recommendations! Even the original repair manual on my 7.5 does not stipulate the plug type or heat range for it at sea level.

 

[eurolarva]

Re: Original spark plugs number? VWB 52119 B

Your motor is circa 1982. Chrylers for that year on a 15 hp were using a L4J plug which would cross to an L82 which is the same plug I use for my 45 hp chrysler. In 83 they changed the spec to a L82C because the L4J was discontinued by Champion.

 

[sentinel]

Re: Original spark plugs number? VWB 52119 B

Great Admiral Larva ! Great !

I guess you have to ask "the Big Brass" to get an answer without a listing to port. Nicely done. Thank you.

Your answer matches the general plug type in the 7.5 Hp I picked up. It came with two nice J4C's....so someone was trying to stay in that general heat range to keep the cylinders cool without fouling.

Judging from the views on this thread....others wanted to know too.

Seaman Apprentice Larry.

 

[eurolarva]

Re: Original spark plugs number? VWB 52119 B

Actually Roscoe outranks me by about a ton. Chrysler stayed with the same plug for throughout its twenty years. Some different type of ignitions required gapless plugs like the L20. One of my first posts here was on what type of plug. There is an L84 that is like the next hotter plug. It will help trolling but running wide open is not advised. Plugs may foul if you troll a lot but they are cheap. Probably around 2 bucks each.