Brian, You can expect the richer mixture when adding carb heat, and you would expect to have to lean the engine when you add carb heat. Yours sounds a little excessive, indicating a problem somewhere else. You should not experience large changes in mixture just by changing the throttle setting. That is the carbs job to maintain mixture settings due to a change in throttle postion. Either your jetting is WAY off, or you have a vaccum leak, or your carb bowl venting is somehow presurizing the float bowl, or you have too much fuel pressure. Has this carburator been overhauled or is it new?
--- Brian Kraut <eng...@earthlink.net> wrote: > 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 ===== Scott Cable KR-2S # 735 Wright City, MO s2cab...@yahoo.com __________________________________ Do you Yahoo!? Free Pop-Up Blocker - Get it now http://companion.yahoo.com/
