AC B runs poorly

My AC B will start with the choke about 3/4 closed and will run only with that choke setting. Took carb

off today and soaked it and blow out all the valves . Put back on , no better. Tractor doesn,t run

good enough to use. What else can I do? Sounds like its not getting enough fuel but its getting into

the carb , a good flow from the tank. It has a castiron Zenith carb. I don,t know what to do next.

Thanks Robert in Md.
 
Remove the plug from the bottom of the carb and let the gas flow through the carb for several minutes.
You must have a restricted flow from the tank. It could be the gas cap vent, remove the cap and see if that helps, or an obstruction in the tank or fuel line. LOL Bob
 
First off you can't remove a carburetor disassemble it, soak to remove crud and put it back on in the same day.
Your lucky to dissolve the build up of evaporated gas and dirt in two days soaking alone.
I start by boiling the carburetor on soap water before removing one screw which will loosen the dried crap that acts like glue in the jet threads. I then disassemble the carburetor and drop into a carburetor cleaner basket for no less than over night. I then run drill bits in the passages with my fingers as well as run taps in all threads. I then put all parts back in the basket for a short time before rinsing with water and blowing out with compressed air. I sometimes boil the parts the second time after soaking if the build up is not coming out easy.

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If the main jet in the bottom of the carb is plugged it will also give these symptoms. If it is plugged with varnish you will have to remove it to clear the clog. Access is thought the bottom needle (or plug) in the base of the bowl (no need to split the carb on a zenith). Make sure you grind a screwdriver to fit it properly so you don't damage the brass jet.
 
Liquid laundry soap. My wife buys non scented All but any liquid would do the same. I would think the powder laundry soap would do the same also. I use a full load cup of the liquid soap in that pan. It never suds up when boiling. It does soften the crap inside and out.
 
I found the problem. After I soaked the carb and blew out all the passages I reassembled the carb

without any improvement in the way the B ran. Last night I was looking for something on the

workbench and there was the AC B,s carb venturi. Another senior moment, I had assembled to carb.

without it. Replaced the venturi this afternoon and the tractor runs fine. Getting a cotter key

in the govenor shaft behind the carb is sure a pain to put in. Sorry for my mistake, its like

walking to the barn to get something and forgeting what I went for.
 

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