Carb Return Spring Strenght

[Gary J.]

Am I the only one having issues with the return spring capabilities on a small block 300HP with a holley 3810 carb. I had a service replacement carb and the stock return spring and its strenght was never enough to get it to idel down properly, I always needed to add another spring internal to the correct spring. Same thing is happening with an original 3810 professionaly rebuilt with another new standard in appearnce return spring. Anyone have a solution other than a spring added to the original style?
Thanks, Gary

[Bob R.]

Re: Carb Return Spring Strenght

Gary,
I had the same problem with a reproduction spring on my 63 with a carter carb. I ended up using a spring I got at a parts store. It looks nothing like the original but it works.
Save the reproduction for judging.

[Timothy B.]

Re: Carb Return Spring Strenght

Gary,

I can only offer some suggestions as it seems odd that two carburetors share the same problem.

Look for problems in the lever and accelerator pedal and also where the ground strap attaches to be certain there is no hard spot around the idle position. Also, make sure the linkage is adjusted properly so at WOT the lever just touches the firewall then two turns in on the rod threads.

If there is a carburetor problem it will be in the throttle blades or wore throttle shaft bore. Like I mentioned above, it's highly unlikely both of the carburetors have this problem but not impossible..

The 3810 on my car will return to idle with just the helper spring on the primary throttle shaft, of course I would never trust that..

[Gary J.]

Re: Carb Return Spring Strenght

Thanks Bob & Tim, please define WTO. Gary

[Timothy B.]

Re: Carb Return Spring Strenght

Gary, Sorry, It should read WOT (wide open throttle)

[Stuart F.]

Re: Carb Return Spring Strenght

I have always, repeat, always found the standard spring on my 63 to be too weak to hold a good idle from day one. I did all the checks that Tim suggested, even ran without a ground strap for awhile as it broke. I also went through the entire era of believing at least one after market supplier would have the correct "white spring', but none of them were ever right and had to be modified to work by cutting down the long end. I now use the 64 and up spring (black) and it is better, but still not adequate. I use an external booster spring (1/4" dia) in such a way that I can take it off for show. I have gone through three AFB carbs on this car with the same problem.

Stu Fox

[Bill C.]

Re: Carb Return Spring Strenght

My experience with all the vendors Ihave tried is that all the repo springs are much weaker than originals, always need at least two and sometimes the NAPA or Help aftermarketr springs. Too bad nobody got it right.

[Mike G.]

And here I thought it was just me

I've been fighting this problem ever since I put my '65 300hp car on the road earlier this year. Never been able to find any binding with the accelerator linkage, throttle plates or anything else. I'm off to ACE hardware this week to find a HD spring or, failing that, a "helper" spring to siamese (oops I mean conjoin) on.