Martin “60” spark plug

[jimk]

I picked up a 1950 Martin 60 and waiting on a few parts. I cant find what the spark plug is supposed to be for it. I saw one place that had a Champion j8c listed but not sure if that is the right one? It seems to be in pretty nice shape for a 72 year old motor and hope to get it running!

[Buccaneer]

These are Autolite numbers. You can cross reference them on the Net
if you like champion.

Prepare to be boarded!

[jimk]

Thanks! Looks like it will work as it crosses with the XST458. Dont think I need the high speed one. Autolite Isnt very common around hear. At least not like Champion and NGK.

 

• This reply was modified 3 years ago by jimk.

[joecb]

Martin “60”   takes Champion J8

Joe B

[jimk]

Will J8c work? Cant find a J8.

[dave-bernard]

Yes!!!!

[joecb]

J-8  , designates the “8” is the heat range. The modern designation is J8 C  , The “C” a Champion marketing thing supposedly to designate a copper core?? If you look in vintage references for spark plugs you will often find  a suffix of “J”  , as in J8J … the “J”  was a OMC initiated designation for plugs meant specifically for outboards. The “J” indicated a plug with a shortened ground electrode. The ground electrode is shortened such that it extends only half way across the face of the positive electrode, this supposedly to minimize the chance of a carbon particle getting stuck in the gap and shorting out the plug.

As for heat ranges ;  with Champion plugs the higher the number that hotter the plug. It’s the opposite with NGK

Joe B

[jimk]

Thanks for the info! Now to see if I can get it purring.

 

[Tubs]

I don’t know about your 60 but the J8C is to long
for my 75 Twist shift. They wont fit under the
cover and can short out the plug through the boot.
The original J8J not only had a shortened ground
electrode but was also a physically shorter plug.
If you find that this is the case with your motor
you’ll need to use a shorter plug.
Tubs.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

[joecb]

Good “catch” Tubs… Yes, that could be a problem with the Martin. It sure is with the Evinrude Zephyr and their close-fitting shrouds. Although Champion makes a short body plug, the terminal is not threaded to take a nut and ring wire terminal. I found that NGK does make short body plugs with threaded ends (although metric thread) . I use the NGK  BM7A in my Zephyrs , the heat range seems comparable to the Champion “8” .    If you need to change from the push -on terminal to a nut, you will need to look for the correct metric thread.

Joe B

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