[TR] TR4A plug check

Randall TR3driver at ca.rr.com
Sat Nov 4 15:18:51 MDT 2017


> Have 1500 miles on rebuilt engine and Stromberg carbs.  Was running good.
> Recently seemed to have lost a little power.  Pulled the plugs.  Looking
> for some clue as to the reason for what l found... #1 plug was black and
> slightly wet.  #2 looked like the mixture was good.  #3 was black but dry.
> #4 looked a little lean.  Last pulled the plugs at about 1000 miles.  They
> looked normal.  Of course, I'm trying to figure out why plugs on the same
> carb are so different.  Did not get them mixed up.  Appreciate any ideas.

Check compression and valve lash; then valve lift.  I suspect you've got one
or more valves that are leaking; but might be a cam lobe that is going away.

-- Randall



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