Since I have put in an air/fuel ratio gauge I have noticed very wide changes in the air/fuel ratio at different throttle settings and with small changes in the amount of carb heat used. If I adjust the mixture for a perfect 14.7/1 ratio at about 75% power it will stay there, but increasing the throttle just a few hundred RPM will peg the meter at full lean and decreasing it to about 50% power will peg it at full rich. Partial carb heat will also peg it at full rich.
I have determined that this has been the cause of my engine problems all along. I have been needing partial carb heat to keep the mixture from going to lean at times at high power settings, and sometimes I was getting a fouled plug and loosing a cylinder after pulling the engine back to low power settings. Anyone else had any similar problems with the Zenith 1821 carb? Is it normal to have to fiddle with the mixture every time you make a power change with one? Is it just not a very good at keeping a consistent mixture at different throttle settings or is there something wrong with mine? Would having the main mixture a little lean and the idle mixture a little rich make as big a difference as I am seeing in the 50-100% power throttle range? Signed, All Mixed Up
