Choke heat problem solved

[Bob S.]

THANKS GUYS. The problem was with the main body. There was no hole in the bottom as I showed in the photos last night. Why? That's a good question. I went over to a carburator repair shop this morning that specializes in older stuff, mainly Holleys. He had an old WCFB in his junk basket and we looked at the main body. It had the vacuum hole where it should have been on my carb (same casting number). We measured the size and depth and found where it tied back into the throttle body. I came back home and drilled a 1/8th hole about 7/8ths deep and we now have vacuum at the choke which in turn draws the heat up the choke tube and after a very short time opens the choke fully. By the way Timothy, it is full manifold vacuum.

Thanks once again guys. As usual this forum is full of great knowledge and good people willing to share.

Sully

[Stuart F.]

Re: Choke heat problem solved

Bob;

Good to hear you have your problem solved. Congratulations.

Where did you measure your vacuum? Reason I ask is that I don't doubt that the way you re-established your internal porting you would see a strong signal at the choke housing. The path used on my AFB's is similar in that regard. However, my measurements upstream at my clean air hose to the exhaust manifold heat tube show a definite restriction, dropping the signal to less than 2 Hg. Tim said his showed otherwise. It would be interesting to discover why. Granted we are each talking about different engine configurations, but the basic principles should be nearly the same.

How well is your engine running now? Have you noticed any difference in your idle and low end performance, other than the fact that you now have full choke function?

In my situation now with an electric choke, I'm glad to remove that "vacuum leak" from the jetting equation though I would imagine Carter determined their original jetting based on the presence of it.

Stu Fox

[Clem Z.]

Re: Choke heat problem solved

Bob;

Good to hear you have your problem solved. Congratulations.

Where did you measure your vacuum? Reason I ask is that I don't doubt that the way you re-established your internal porting you would see a strong signal at the choke housing. The path used on my AFB's is similar in that regard. However, my measurements upstream at my clean air hose to the exhaust manifold heat tube show a definite restriction, dropping the signal to less than 2 Hg. Tim said his showed otherwise. It would be interesting to discover why. Granted we are each talking about different engine configurations, but the basic principles should be nearly the same.

How well is your engine running now? Have you noticed any difference in your idle and low end performance, other than the fact that you now have full choke function?

In my situation now with an electric choke, I'm glad to remove that "vacuum leak" from the jetting equation though I would imagine Carter determined their original jetting based on the presence of it.

Stu Fox

interesting as those holes are cored in the die that makes the casting. we need someone with a original front WCFB,no choke, off of a corvette to see if that hole is cored the whole way thru in that casting or was this just a screw up.

[Stuart F.]

Re: Choke heat problem solved

Clem;

Seems ironic thatit would take this many years to be discovered. I'm betting on your theory that it is a center section (main body) from either a front 4-barrel from a dual quad Vette or some other animal that does not have the choke. Did Bob note the casting number(s) in one of his previous threads on the subject?

Stu Fox

[Clem Z.]

Re: Choke heat problem solved

Clem;

Seems ironic thatit would take this many years to be discovered. I'm betting on your theory that it is a center section (main body) from either a front 4-barrel from a dual quad Vette or some other animal that does not have the choke. Did Bob note the casting number(s) in one of his previous threads on the subject?

Stu Fox

if he did i did not pay any attension to it as i am not a numbers man. same with engines give me the year,displacement and HP and i know what you are talking about. the "L"s mean nothing to me.

[Stuart F.]

Re: Choke heat problem solved

Clem;

I can appreciate what you say. I never ever referred to my 63 as having an "L-76" or "SHP" engine before posting on the board, rather a 340 hp or 327, etc.

I checked back to Bob's first thread and he posts under a 59-60 avitar, and he stated he had a base 230hp/283ci with a Carter #2818-S WCFB. He also noted that his heat riser had the butterfly removed. I had suggested he might want to switch to a full function heat riser. I think that would be more appropriate for a base engine.

Stu Fox

[Clem Z.]

Re: Choke heat problem solved

Clem;

I can appreciate what you say. I never ever referred to my 63 as having an "L-76" or "SHP" engine before posting on the board, rather a 340 hp or 327, etc.

I checked back to Bob's first thread and he posts under a 59-60 avitar, and he stated he had a base 230hp/283ci with a Carter #2818-S WCFB. He also noted that his heat riser had the butterfly removed. I had suggested he might want to switch to a full function heat riser. I think that would be more appropriate for a base engine.

Stu Fox

hard to believe that no one caught that in all those years. i hope some on with a original front 2X4 carb setup can come thru about if that passage is blocked off or not. if it is not blocked on those carbs then bob's casting was a defect.

[Bob S.]

Re: Choke heat problem solved

Stu and Clem - This car has been apart for 23 - 25 years. I have owned it for 3. The carb was overhauled before I acquired the car so I can't attest to what was done. As to the casting numbers, they are all correct according to the JG. Air Horn - 6-1396, Main Body - 0-1208, Throttle Body - 1-1582. It is looking very obvious that it was rebuilt with a different main body than the original.
Stu - I hooked up my vacuum guage to the exhaust manifold end of the choke tube (after taking it out of the manifold) to get the reading. As to performance, I have not had a chance to check that yet. I just fired it up last night to verify the vacuum and that heat was being pulled up to open the choke.
Sully