The Black and sooty plug is a DEFINITE indication to an over-fuelling problem.
Another side of this is that the plugs will "carbon track", which means that after a period of too much fuel burning around the plug, the ceramic insulator will actually form a hard carbon coating that cannot be cleaned or burnt off.The plug will misfire deep into the plug and cause a poor combustion cycle within each cylinder and continue for every revolution of the engine until it cannot fire the mixture at all.....cough, splutter and stop. Sound familiar???????
My suggestion to you now would be to bin those plugs(I know this is hard to do with a set of new plugs!) and put in a complete new set. Fire the motor straight away and let run for 60 seconds, then stop and pull a plug out.Check for any black soot( there will still be some excess in the combustion chamber),clean the plugs and repeat again for another 60 seconds.If you find it is running fine, get a buddy to follow you and give it a good higher speed long run to burn off any excess and then check plugs again. If all is clean.......hey presto......I don't think you will have this problem again. If you do.....look at the plugs straight away, if they have sooted up enough to stop the engine, the fuel system is the ONLY Fault.(too much fuel, forget the ignition etc.)
Old stale fuel will also cause the plugs to do this.
ONLY run fresh clean fuel.Even a cupfull of old fuel left in a second hand tank can effect the plugs in this way.
Have a go and let us all know how you go.
All the best.Doc Bob.

Last edited by doc bob; 05/30/2008 1:14 PM.
"It's not a wreck......It's a natural resource!"
Quote-Doc Bob circa 2006

DOCS CLASSIC GARAGE
Specializing in Hot Rods,
Customs & Street Machines.
My pictures at..........
1936 Chev 1/2-Ton Holden Body


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