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tucsonjwt · 12-06-2014, 02:30 PM

Just a thought, chokes have been the big problem with all of the carburetors on my old squares.

I would stop when it backfires and pull off the air cleaner to make sure that the choke is all of the way open. If the choke is not functioning correctly, you are supposed to bend the connecting link to adjust the choke - I was never able to do this successfully. In fact, on all automatic chokes, I could either adjust them to close all of the way when the engine was cold, or open all the way when the engine was hot - but I could not get both conditions - so it would either give good cold starts or hot runs but not both. So, I now use manual chokes only.

Backfires are sometimes vacuum related (so I read) - you might double check the vacuum hose routing - on both the carburetor and the other end of the hoses.

12-06-2014, 02:30 PM	#7
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,198	Re: Misfiring after installing new carburetor. Just a thought, chokes have been the big problem with all of the carburetors on my old squares. I would stop when it backfires and pull off the air cleaner to make sure that the choke is all of the way open. If the choke is not functioning correctly, you are supposed to bend the connecting link to adjust the choke - I was never able to do this successfully. In fact, on all automatic chokes, I could either adjust them to close all of the way when the engine was cold, or open all the way when the engine was hot - but I could not get both conditions - so it would either give good cold starts or hot runs but not both. So, I now use manual chokes only. Backfires are sometimes vacuum related (so I read) - you might double check the vacuum hose routing - on both the carburetor and the other end of the hoses.