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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Eastonfrench on March 22, 2016, 07:16:16 am

Title: Really Simple Hot Air Choke Question
Post by: Eastonfrench on March 22, 2016, 07:16:16 am

Hey Guys,

So my quadrajet has the hot air choke. And the problem I have, is that I dont think the choke thermostat (the coiled spring) travels enough.  If i turn the plate to where the choke butterfly is closed for nice easy starting, then when the truck is running temperature, the choke only comes halfway off. If I adjust the choke to where it is all the way off at running temperature, then when its cold I can hardly get the truck to start up. In other words, I need the choke spring to move, lets say, 45 degrees of rotation to move my choke from closed to open, but my spring only moves 25 degrees.

I checked that there is no holes in the hot air tube, and no leaks around its ports, so i am sure that the choke thermostat is getting plenty of hot air. TO confirm, I took the choke thermostat out and put it in hot water to confirm that it only moves a little bit, it doesn't open a bunch like I would like.

SHould I buy a new choke thermostat? Can those things go bad and lose their spring? or is it not getting hot enough? I really am not sure. Thanks!

Title: Re: Really Simple Hot Air Choke Question
Post by: Stewart G Griffin on March 22, 2016, 07:24:05 am

Yes, it's possible chokes go bad.

Another thing to check is when the engine reaches regular temp, very quickly and lightly touch the choke cover and it should be VERY hot.  Then you'll know that it's getting hot air.

Title: Re: Really Simple Hot Air Choke Question
Post by: Eastonfrench on March 22, 2016, 08:27:45 am

I wouldn't say it's getting REALLY hot. On my temp gauge, running temperature is the needle 1/4 the way between C and H.

Any chance I should run a hotter thermostat to get the engine hotter?

Title: Re: Really Simple Hot Air Choke Question
Post by: Eastonfrench on March 22, 2016, 09:00:39 am

Just got to where I can work on it. So, vaccuum is supposed to pull hot air through the heat tube right, well if I unplug the upstream side of the heat tube (the side that goes into the top of the carb, not the end that goes into the inegral choke), i feel no suction. Shouldnt i feel the tube puling for air?

To confirm the choke stove isnt broke, I popped the hot air tube off of the choke, and put my finger on the choke thermostat air inlet and felt no suction. How can I fix this?

Title: Re: Really Simple Hot Air Choke Question
Post by: blazer74 on March 22, 2016, 01:03:13 pm

The vacuum is from a very small passage from the carb body thru the fed choke housing leg.

Has a small plastic piece in between the carb and choke.

Should also have a gasket under the choke to seal. There's also a seal on the choke lever to the inside of the choke housing.

Don't know if u would actually feel the vacuum. Never bothered and convert to electric on my own.

The choke thermostats do go bad.

Title: Re: Really Simple Hot Air Choke Question
Post by: blazer74 on March 22, 2016, 01:08:37 pm

https://books.google.com/books?id=IuQDAAAAMBAJ&pg=PA113&lpg=PA113&dq=tvs+choke&source=bl&ots=wg2wilkWY6&sig=sRhmJqioqbnR-ujcgUwOk0CYpdg&hl=en&sa=X&ved=0ahUKEwimoYDJ76fLAhVM4yYKHVgzDZ4Q6AEIMzAI#v=onepage&q=tvs%20choke&f=false

Title: Re: Really Simple Hot Air Choke Question
Post by: Eastonfrench on March 22, 2016, 03:33:07 pm

RESOLVED: the choke thermostats gasket was missing. So vaccuum was not being pulled. Put some gorilla tape around it and she's good as new!

Title: Re: Really Simple Hot Air Choke Question
Post by: philo_beddoe on March 24, 2016, 05:27:10 pm

Is there anything gorilla tape cant do??

Title: Re: Really Simple Hot Air Choke Question
Post by: zieg85 on March 24, 2016, 05:31:52 pm

Gorilla glue is also a favorite of mine

Title: Re: Really Simple Hot Air Choke Question
Post by: philo_beddoe on March 24, 2016, 09:34:08 pm

I know, but the regular stuff always foams out white, expands too much. However, works great.