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1970-dart

1970-dart

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here is a pic i got out my Holley 1920 manual of the pump diaphragm.. I have been having many different issues with my carb and I know I need a new one but right now with a 20 day vacation coming up buying expensive unneeded parts is not an option.
I rebuilt the carb with the walker kit and an new float it adjusted fine and it runs good other than the occasional flooding issue and now and then percolation which I know I can fix with instructions from other methods found on here..
but after looking more at the diagram I realize that my carb does not have a drive spring ( i must have lost it )on the diaphragm stem. Now of course I know I need this spring as it is part of the carb but also other than the now and then flooding issue it runs fine..
My question is would missing that spring cause the occasional flooding issue and the percolation issue that I did not have before the rebuild. Also the kit came with a thin base gasket and think one as well.. I used the thin one because thats what was on there to begin with but somewhere someone said use the think one but i'm not sure the studs are long enough to use the thick one.

Thank you in advance

drivespring.jpg
 
Well, your percolation issue is definitely due to using the thin gasket, and has nothing to do with the accelerator pump. If you switch it with the thick gasket, you'll probably stop boiling your fuel.

Not having an accelerator pump spring though would contribute to flooding issues, since you're trying to start the car without being able to prime it. If you take off the air filter, look down the carb throat, and hit the throttle with your hands, you should see a little squirt of gas go into the motor. if you don't, there's your issue.

Though, if it's the accelerator pump, if you step on the gas really suddenly from a dead stop, the engine should die, or at least stumble. If you get good throttle response though, the accelerator pump isn't your problem.
 
ok put on the thick gasket and it seemed to cure the peculation issue up nicely.. It still has some fits and i'm not sure if its a flooding issue or something else..

When it is running down the road at highway speeds it runs like a champ and has plenty of power all through the band with no pinging or stumbling on take off.. What it does is sometimes not always at lower rpms like coasting to a stop or sitting idle at a light or traffic it will start to run a little rough. If i rev it up a bit it clears it out and goes back to a smooth idle until its next random time to do it again..

It is not coming out the top of the float bowl vent like it used to so I am assuming the float is not to high anymore. Could this be the float is maybe to low or my adjustment is still off or maybe needle and seat issue.. When I rev it up some to clear it out back smoke coems out so I figure thats is from to much gas going into carb but it just idles a little rough it never quits or has gas running out of it anywhere..

Thanks in advance
 
That spring might create a small amount of back pressure on a check ball in the bottom of the pumps cavity. In that case you could have fuel leaking past the check ball and slowly flooding the engine.
Similar example was a carb on a 86 Ford 2.8 ltr V6. Somewhat common fault was extremely rich mixture. Simple repair was to remove the top of that carb and peck the ball with a drift and hammer so the casting conformed to the ball radius again.
 
i have to replace the spring anyway and also will put in a new pump diaphragm and see where that takes me

thanks
 
hi Dan or anybody else

i have a question for you on the spring for the pump in my carb..i have been doing lots of research on this to find out all the info i can so i dont have to ask to many questions.. I was going to buy a new pump return spring and then i found this thread

http://www.forabodiesonly.com/mopar/showthread.php?t=124987

and it looks like you said that only the round stem pumps needed the spring and not the flat( which is what i have) but the pic out of the manual shows a spring on the flat stem pump.. i know that could be just for illustration but Im more lost now than i was to begin with if that is possible lol

and also i see in the pics on the walker site there looks to be a little black cap looking thing that goes on the end of the needle and seat assembly and the needle sticks out through it and mine is missing that as well..

thanks
 
Hate to berate you, but I expect others are thinking the same. Anyone attempting to rebuild a carburetor needs extreme attention to details. I don't see how you could maybe lose such a big spring. You should be rebuilding this on a clean table, where nothing can roll away. Put all parts in zip-lock bags and take photos as you go. Your research lacked attention to details. What Dan said was:

"The '64-up units with flat stem have a drive spring but no return spring."
 
BillGrissom said:
Hate to berate you, but I expect others are thinking the same. Anyone attempting to rebuild a carburetor needs extreme attention to details. I don't see how you could maybe lose such a big spring. You should be rebuilding this on a clean table, where nothing can roll away. Put all parts in zip-lock bags and take photos as you go. Your research lacked attention to details. What Dan said was:

"The '64-up units with flat stem have a drive spring but no return spring."
Click to expand...

LOL I hate to berate you but i'm going to anyway.

I wrote some stuff then decided it does not even deserve any more of my attention with a bigger reply than this have a nice day and thanks for your useful info to my question rofl
 
I had the same problems with my Carter 4 bbl. The problem ended up being a stuck float.
 
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