Is there an adjustment to auto-chokes?

[bigd1101]

My auto-choke seems to be a tad high at start-up, so I have to give the pedal a quick pump to settle it down to a slower pace while warming up. One the car does warm, the auto-choke does ramp the idle down to normal. Is there a way to keep the auto-choke from racing at start up?

BTW.....you guys are saints in helping this old coot with my new Merc. A gold mine of knowledge....


Don

 

[cmbrucew]

Don
Does yours have a bakelite cover, held on with a metal ring with three small screws?
If so, loosen the screws and turn the cover just a little bit left or right.

Next day you will know if it helped, or hurt.


Bruce

 

[rotorwrench]

The body that the plastic spring housing fits to generally has a series of equal distance markings for part of the way round the periphery of the housing with a longer central index marking. The round bakelite temp spring housing has a single index mark on it. The specs for each carb can be found in the auto manufacturers data or perhaps a Motors manual or Chilton's. I will tell which mark to align to. The cold start fast idle cam set up generally also has to be adjusted for proper cold start rpm but that is a separate adjustment.

 

[RalphG]

My 52 was converted to manual choke years ago. The plastic cover on the left side is the adjustment for making the choke come on sooner or later. There is an idle speed screw over on the right side, can't recall just how to adjust it as mine needs a little adjusting too. Runs too slow when cold. You can learn a lot of good information on the teapot carburetor at the old car manual project where they have the complete manual. http://www.oldcarmanualproject.com/manuals/Carbs/Holley/H1901-1952/MCarbHoll190119522.html

 

[scicala]

If the choke is opened all the way when warmed up, then don't change the setting of the round thermostat cap.
There is a 2nd speed screw on the carb for the fast idle cam that you can back off some to slow the fast idle down.

Sal

 

[bigd1101]

Don
Does yours have a bakelite cover, held on with a metal ring with three small screws?
If so, loosen the screws and turn the cover just a little bit left or right.

Next day you will know if it helped, or hurt.


Bruce

Should this be done at startup while the car is running or not running and cold??

 

[Zeke3]

Re-read Sal's guidance in post #5 before adjusting anything.

 

[scicala]

Re-read Sal's guidance in post #5 before adjusting anything.

Thank you Zeke.
It's already been said that the choke opens fully when warmed up, and closed when cold. if the engine races too fast on a cold start, you need to back off on the fast idle screw that contacts the fast idle cam.

Sal

 

[Merc Cruzer]

Don
Does yours have a bakelite cover, held on with a metal ring with three small screws?
If so, loosen the screws and turn the cover just a little bit left or right.

Next day you will know if it helped, or hurt.


Bruce

See picture

 

[rotorwrench]

The initial book setting of the temp spring housing usually works for most situations. The old cars had to warm up for a bit due to the way the choke and fast idle system worked. This is something that folks always tried to hurry up in their haste to get to work in the morning. In the heat of the summer, the fast isle system usually won't pull cam to fast idle but carburetors always liked being warmed up a bit before hitting the road anyway.

We are so used to modern fuel injection now that we are spoiled. You don't need to wait to get moving but the engine should still be babied till it warms up to operating temperature. Those that warm their engine up by blowing on down the road like the wind usually put a lot of premature wear on their engines.