View single post by Jim Sohl sn 11210
 Posted: 07-15-2015 12:36 am
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Jim Sohl sn 11210

 

Joined: 01-20-2015
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 Forgive me if this has been covered before, it is a long thread.  On acceleration from an idle, a very temporary rich mixture is needed.  Many carbs do this with a squirt of gas from an 'accelerator pump,'  Dell's do this as do Webers.  The Stromberg method is different.  The air valve, the large cylinder that goes up and down with air flow, is  prevented from going up as fast as the air flow goes up upon opening the throttle plates from low (idle) speed by a 'damper.'  The damper is the piston-like thing that goes into the top of the carb.  Unscrew the knob at the very top of the carb and gently pull the damper out.  It should move freely, but slowly, as if it were a tiny shock absorber.  If fact, that is almost exactly how it works, by forcing oil through a small passageway, thus slowing down the movement of the air valve.  Check the oil level in the damper tube.  It should be about half-way filled with oil.  If not, there will be far less damping and the air valve will move up very quickly, quick enough that the temporary rich mixture goes away too soon, resulting in stumbles, misses etc.  I do not frankly know what kind of oil is supposed to be used, I have used 20/50 in the past with no complaints.  If your dampers have oil and are slowing down the air valve, you problem probably will be found elsewhere.  I'm sure this has been posted by others, just an FYI.
good luck!
Jimmy