adjusting air fuel mixture

W

wbs

Senior Member
hello- i don't start my t very much but when i last ran it 2 months ago, the car ran well with the spray needle turned out about 1.5 turns out from seating. when i started it yesterday, it was very hard to start and after running, it ran smoothest and fastest when i turned the needle almost all the way in. is this usual? if not what is wrong? i drain the carb and tank each time after running.
 
My understanding is that the mixture should be set at 1/4 turn or so for proper running, maybe a little richer while warming up. 1.5 turns is very rich, but I had that same thing with my Model A which indicated a gummed up carb that needed cleaning. Gas today seems to be a problem.
 
Here's what I got from your post: you changed nothing, it was running/starting OK then one morning it was hard to start. First off, although it could change when the car heats up, 1 1/2 turns open is the accepted starting point for the needle adjustment. Might need less when hot and it might have to be opened a bit when starting in cold weather. There isn't a "normal" situation where it allows the car to run well with it 1/2 a turn open. I believe you're in for a carb re-build as an internal passage is partially clogged. Draining is usually a good thing but not always.
 
Agree with Charlie - you let the gas go bad and now it doesn't run right. You need to drain the tank and carb if the car is not going to be run for several months to avoid this.
 
That depends if the needle is giving the illusion of sitting almost 100% closed or not, as sometimes the nut that tensions it can tighten up and give a false reading. It happens on mine anyway... But if it is 100% closed and still running that sounds like the jet may have some damage.
 
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