Small Engines (Lawn Mowers, etc.): Black carbon on end of spark plug, roto tiller, rich mixture

Question
Hello,
I got my dad's huffy/huffman roto tiller out this spring and tried to start it (it worked fine last year).  I got it to start after several pulls, let it run and shut it off (it was too wet).
The next day I could not start it.  Sometimes it would kick, but not run for more than a few seconds.
I determined it was flooding and maybe the plug was too fouled (it wasn't black or burnt).
Went to get a new plug and got one of those E3 plugs.
Right after putting it in, it started on the first pull.  However, I noticed while running it didn't have much power and the exhaust was pretty thick (more than normal).  Eventually after 5 or 10 minutes of use, it stalled.  It would start, but only for a few seconds.  I took the plug out and it was burnt black on the bottom.  The combustion chamber was also black (it wasn't before).
I had changed the oil and cleaned the air filter.
Also, after putting the E3 in I noticed an ooze of gas from around the plug. I put some teflon tape on it and it stopped.  (both the plug threads and the socket looked ok and it seem snug).

Is this a carborator problem?  Whey would it be off, since nothing has changed since last year?
Thanks,
John


Answer
Hi John,

Sorry for my delay.  It was a busy holiday here.

I am not familiar with the E3 plug.  Make sure you are using the correct plug and if it still burns black, then that would indicate a rich mixture.  You could try closing the high speed mixture screw a little.  The carb may be gummed up with old fuel residue and you would have to disassemble, clean all the small internal openings and blow it out with compressed air.

I am swamped with questions and can't give follow up answers until next week.  Sorry.

Good Luck,
Michael