From: W P. Fricke
From: Barbara Boedigheimer <Boedigheimer@planacc.com>
Subject: [oletrucks] tune up
Barb asks: I am trying to fine tune my 49 GMC 228. It runs pretty good but
while
idling every once in awhile will backfire thru the carb...
I too experience some carb farts every once in a while. But not while idling.
Only when accelerating hard. Its usually when the engine hasn't fully warmed up
to full running temperature and I hit the pedal. Usually backfires through the
carb are an indication of a 'too-lean' mixture. If you backfire through the
exhaust, your mixture may be too rich. Mine is a Rochester carb. I haven't
pulled it to do a rebuild or check the size of the jet(s). I don't even know if
there are slow and main jets in the thing.
The other condition I have experienced is that it runs much smoother from a stop
and when accelerating out of a gear shift if the choke is out a little. I had
the throttle hooked up but the pedal kept getting stuck and I'd have to reach
down and pull it back, so I dis-connected it. So I wonder if the carb back fire
and the general smoothness of acceleration are connected symptoms of a overly
lean mixture.
To top things off, for the first time in a year I was driving home when the
engine started to stumble like it was running out of gas and quit. I sat for
probably no more than 30 seconds, started it back up successfully and drove home
without a problem (about 12 miles). This has happened twice. Plugged fuel
filter? Faulty pump?
Patrick
53' 5-window 3100
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