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SkyHarborCowboy
02-09-2009, 06:43 AM
I gave a friend of mine a 1980 something Johnson 150HP Outboard and he asked me about the sparkplugs. He fouled them and told me they were Surface Fire plugs. I have never heard of them but he says they dont have the more normal ground tab under the electrode and cost about $15 a piece he says. He was wondering if you could use the more normal and less expensive plugs in thier place.

I dont have the exact part number to tell you guys but can you clue me in on this type of plug?

Joe

John Schubert T*A*R*T
02-09-2009, 07:07 AM
I gave a friend of mine a 1980 something Johnson 150HP Outboard and he asked me about the sparkplugs. He fouled them and told me they were Surface Fire plugs. I have never heard of them but he says they dont have the more normal ground tab under the electrode and cost about $15 a piece he says. He was wondering if you could use the more normal and less expensive plugs in thier place.

I dont have the exact part number to tell you guys but can you clue me in on this type of plug?

Joe

Switch to something like a L77J4 or the correct heat range for the paarticular motor. When we first ran the OMC V-4's in racing in the early 70's that is what we used but quickly switched to the L77J4's which today might be L77JC4's. Could also find an NGK equivalent which today are better plugs.

Mark75H
02-09-2009, 08:39 AM
The surface gap type is a very cold spark plug first used with early solid state ignitions.

This stuff will blow you away:

http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F3599030

http://www.google.com/patents?id=bddmAAAAEBAJ&dq=3599030

http://bulk.resource.org/courts.gov/c/F2/689/689.F2d.740.81-1957.html

http://patimg1.uspto.gov/.DImg?Docid=US003599030&PageNum=2&IDKey=42D6CC38AC7F&ImgFormat=tif

Tomtall
02-09-2009, 06:13 PM
Sam - Good read. I was never aware this dispute was so heated between Armstrong and Champion. Thanks for sharing.