The Stovebolt Site Forums The Shop Area Engine Shop Throttle kicker..?

On our Rochester B carb the screw holding the throttle kicker plate and spring fell off. The screw is about 1/8" long by 10/32" threads. I used a bottoming tap to cut more screw threads in the corosponding hole on the carb.There was at least another 1/8" of depth in the screw hole so a longer screw could be used with a bit of locktite. The part that flew off is called a throttle kicker...what is its primary function and how does it work with the throttle? I assume it's a kick down from high idle. Our idle would not stay set because the screw was just hanging on by a thread....literally. I was told that this screw is always a problem with B model carbs. Tiny screw and hardly any threads in the hole....I will find out tomorrow if my repair works.
Steve

Not enough information- - - - -is the part operated by vacuum or electricity? Some early carbs had a vacuum-operated "dashpot" that would ease the throttle plates closed when the pedal was lifted quickly after a snap acceleration to prevent stalling. Later on, an electric throttle stop was installed to drop the throttle plates fully closed on engine shutdown to prevent dieseling from the high idle speeds that early attempts at emission control required. There was also an electric throttle stop on some carbs that kicked the idle speed up when the air conditioner compressor clutch cycled on.
Jerry

It's just a steel plate with a spring on the side of the carburetor. The idle screw sits against the bottom of this lever and the top part is a cam sort of thing on the top of the carb. I think it is suppose to even out the moment when you take your foot off the pedal? I have no idea how it works but it fell off and the truck would not idle. No electronics or dash pots. It works somehow with springs. I did a search but nothing in layman terms that I can understand.
Thanks for the help, Steve

OK, that's the "fast idle cam" which opens the throttle a little when the choke is applied. How about threading the hole to the next larger size, like 1/4-28 or 6MM X 1? You would need to do a little custom fabricating of the bolt or screw but you'd have a full thread to work with.
Jerry

I was thinking of that but the hole itself is quite deep so I used a bottoming tap and that worked well in conbination with lock tite. If that doesn't work I/4"x28 wil work and cut threads easily since the carb is made from zimac (but a bottoming tap must be used as not to break through the carb's wall), A 1/4 inch round head screw would work with no modification a washer sits under the screw head. Not too tight the throttle knocker must freely pivot. The machining aspect of the repair is easy BUT how does the dam thing work....carburetors to me as Winston Churchill once said, " are an enigma wrapped in a mystery".
Steve

There should be a piece of linkage that connects to the choke flap at the top of the carb.

A carburetor is nothing but a chunk of metal with a bunch of precision-drilled holes in it. As long as it's the right application for the engine, clean, and doesn't have a bunch of air leaks from worn-out shaft pivots, it should run three days past forever with very little attention. It mixes air and gasoline at the proper proportions to run the engine at various speed and load conditions with no input from a computer and no electronics and they've been doing so for over 100 years. When the tree huggers and the politicians got involved with their pipe dreams for saving the world, things got complicated in a hurry!

The K.I.S.S. principle goes a long way toward making vehicles safe, clean, and reliable- - - -no help needed from the meddling fools who want to push their own agendas!
Jerry