choke on holley carb.

[69jeepcj]

I have this issue lately.. I have a old 4150 series holley 650 double pumper 4 barrel carb with a manual choke on my jeep (I know, they suck off road). The throttle shaft has a nice vac leak so im adjusting the carb about once a week. The choke used to work fine, but now has no affect on the engine. You can pull the choke out untill the engine dies with no change in idle. This happend after i did a adjustment on the carb, not this last weeks adjustment but the week before. I have adjusted it a couple times since with no luck. Any thoughts as to why this happend and how to fix.. It has worked all summer long just fine.
Thanks .

 

[superj]

no idea. the one on my holley doesn;t do anything either

 

[flatie46]

I've never worked on a holley. I have friends that run 'em on there hotrods. If the throttle shaft bushings are worn they'll let air in contradicting what the choke is tryn to do. I have heard that holleys are sensitive in that if they backfire thru the carb they'll blow the powervalve and run crappy till you change it. If had run somewhat ok with the worn bushings till now maybe you have anthor leak, like the intake, vac line or the most common that happens to me carb base. Do the manual choke on those have a fast idle cam set up?

 

[superj]

Yes, they do. Mine just doesn't work so i leave it locked open because i have to buy another element for mine.

Mine doesn't have the backfire issue though and a choke isn't requird where i live, ever.

 

[flatie46]

I've got either a 600 or 650 holley (can't remember which, I've got quite a carb collection) I bought at a yard sale for 30bucks last summer. It had been run very little then pulled in favor of something else. Came with the box, all linkages even the sticker. The guy that had used it had died so there was no info on why he pulled it. I bought an alum intake and was going to try it sometime but mine runs so good with the fact 2bbl I hate to change it.

 

[69jeepcj]

Well when I rebuilt the carb in early spring, some idiot (myself) forgot to put the bushings on the throttle shaft, so that explans my leak but, I didnt know the a vac leak could make the choke not function (not saying it doesnt, just didnt know). that expalins why its not working. the leak at the throttleshaft I guess is alway changing how bad it leaks, which is why I alway have to adjust the carb, so I guess its leaking pretty good right now and has made the choke nonfuntional.. If this makes sense to you guys, sounds good to me for now... Il just deal with it until I can put some bushings in there and see if that fixes it.

 

[flatie46]

The choke flap shuts to richen the mixture. It does this by cutting back how much air the engine gets. If the bushings are gone it's not sealing off at that point and when the flap shuts it just pulls air in from the side. I'd say once you replace 'em you'll have readjust the carb quite a bit. I'm sure fuel mileage will increase quite a bit. I've had throttle shaft bushings that were bad on carbs and you could adjust everything then take your finger and put a little pressure on the shaft and the engine would either idle up or down.

 

[69jeepcj]

Exactly, thats what it does. if you touch the shaft, engine idle changes.. Well, cool this sounds like a pretty easy fix then.. would this explain why my idle screws have gone from 2-1/2 turns out down to a half to 3/4 turn out? right now they are at 1/2 turn out.( just adjusted it yesterday.) thanks for the help.