Thread: Rochester 2bbl Carb on 350 Hesistation/Stall long warm up ?

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Originally posted by Greg
Choke closed after pushing the throttle down once.

when you start the motor how much does the choke pull- off open the betterfly? if its to much could be leaning it out.

Ok here is a pic of the car just started and the choke on. I noticed that it is partially open. If this is the problem would I fix it by bending the tab on this side? It looks like the tab is keeping it from being closed more that or the gold diaphram on the other side is pulling it open to fast. The outside temp was around 78F or so. Please let me know what you think.

This it running with the idle at normal oper. temp and the choke off.

Originally posted by Greg
Ok here are some pics of the carb and linkages. I took some with the choke closed after I pushed the throttle once when cold. I also took a close up of the fast idle cam. Thanks.

next to rhe last pic. is what i was talking about. looks right. everything looks good no reason not to run cold . if you want to you can try by richen the choke a little or bending the pull off rod so the betterfly won't open so far. do his untill you see a dif. in the running of the motor. good or bad. you can always go back. dont do anything untill you hear from denny or some of the others ,might be something im over looking.

ps- have you check the timing? slow timing can do some of what you have.

Thanks. I appreciate it. Yes, I have verified the timing and all ignition components. I also replaced all of the vacuum lines and checked for various vacuum leaks. Thanks Again.

Thanks guys. Do I adjust it by bending the tab up a little? Thanks.

make the choke pull off rod longer.

Great. Thanks. I appreciate it. I am on it. I will post back the results.

Ok, I made this rod longer and it didn't make a difference at all. The choke pulled off the same amount. Man you eyeballed it great. Very close to 3/8s. Still same things. From what I could tell by playing with the carb that didn't seem to pull the choke off sooner. From what I can see on this carb from the way it is setup now is that the butterfly position is completely dependant on the idle speed/fast idle cam. When the idle drops the choke falls with it. Maybe this isn't setup correctly but there is no way I could see for the choke butterfly to stay closed or partially closed as soon as the car is at regular idle speed with the fast idle cam in its lowest position as seem in the pic of engine running at operating temp. If you look in that picture there is a tab/metal flap that will not allow the choke to close once the idle is around 500-600rpm. Maybe this is the problem? When I started the car the electric choke was much stronger than the vaccum diagphram. Please let me know. I made the rod longer and tried different settings but I the choke still opened just as fast and the 3/8 didn't change. The diaphram works fine too. It pulls back when the engine is on but when cold the electric choke seems to over power it and pull it out some. Thanks.

i really dont understand what your doing, but it sounds like you are working on the side of the carb. with the idle cam ,you should be on the other side. at the choke pull off.

No I worked right on the pull off rod. The gold diaphrams rods. I spread the V apart. If you look in the pic it kind of has a V shape. I didn't work on the fast idle cam side at all. Just the side with the electric choke and the choke pull off rod.

This is what I did.

When I spread the rod apart the choke still stayed close to 3/8". It opened up just as fast. I spread it apart more and it still didn't effect the choke butterfly distance to the inside of the carb throat.

ok then that tells me the choke is not tight enough, when the motor is cold the chock should be tight shut and then the choke pull off will force it open. it the betterfly will open by itself when you start the motor then you need to tighten the choke more. if the motor is worm at all you need to let it get cold again. with the motor cold there should be some good tension on the betterfly.

bending that wont do no good, the rod is to short to do anything with it. first one i ever seen with the rod that short. ???? you need to make that rod longer some how.