Carburetor issue?

[Zachary H.]

Hello, I am a new member and new to this forum. Any help you can share would be very much appreciated. I have just recently obtained a 1960 with the base 230 motor. It appears to have the correct Carter carburetor. During the test drive the car ran very nice. My issue is after the motor warms up the idle will not come down below anywhere from 1300 to 1800 rpm. It starts great and runs very smoothly aside from this issue. I have had the car for two weeks and driven it two times as I am in a cold weather climate. I am not sure what fuel was in the tank previously but I added 10 gal of 98 octane unleaded ethonal free fuel. Not sure if this has anything to do with the issue. Thank you,

Zach Hamada

[Michael W.]

Re: Carburetor issue?

Most likely it's the high idle (choke) linkage on the carb is stuck. Not a rare problem.

Don't waste your money on 98 octane gas. Pump premium (91 or 93 octane ) is more than sufficent.

[Edward J.]

Re: Carburetor issue?

Zach, there is a choke coil in the black housing on the side of the carb that uses heat from the exhaust manifold that are routed through a tube on top of manifold, does that tube get really hot after the car runs? If the choke butterfly is not fully open after a few minutes of running the fast idle cam on the drivers side maybe staying on and not stepping down to curb idle.If you have a service manuel it will show you how to adjust the choke coil, just be sure that the tube gets really hot when running.( be careful it can burn your fingers)

[Zachary H.]

Re: Carburetor issue?

Thank you Michael and Edward. I will check on those ideas. Edward I thought it may be the fast idle cam. My service manuals are on the way, christmas gift. Until then maybe I can find the proper way to adjust on line or on this forum. The choke butterfly does not completely open after a few minutes. Michael, my only concern about pump premium is the ethanol. What are your thoughts on this? I sprayed the linkage completely with wd 40 as it looked stuck and a little corroded. This unfortunately did not solve the problem. Thanks.

[Michael W.]

Re: Carburetor issue?

The ethanol subject has been well and truly thrashed to death many many times. There's two camps

1) It's been around much of North America for 20-30 years and there's no credible evidence that it causes damage. There's no real operational issues outside of the gulf states area where owners mention occasional percolation and/or vapour lock which can frequently be avoided with use of non-ethanol pump gas.

Here's a look inside my own car's gas tank which has been given a diet of E10 for at least the last 20 years



vs.


2) The internet says that the sky is falling. A person can never be too safe, so I'll spend my kid's inheritance on ineffective additives that fix 'problems' that never would have happened in the first place.

Guess which camp I'm in?

[Rob M.]

Re: Carburetor issue?

When you loosen the three screws holding the black bakelite housing of the choke spiral bi-metal you can rotate it to ensure its proper setting for hot-engine condition. After setting it tighten the screws (not over tighten!) and you should be good to go.

You might also change the idle setting using the gas cable adjustment.

[Richard M.]

Re: Carburetor issue?

Zach, welcome!

Yes, check the black choke cap(pic 1) as Rob mentioned and adjust to ensure the butterfly is fully open when hot. It may be very simple.

If you have the original WCFB, it may have the integral idle screw and fast idle adjust cam setup like below in pic 2. These are a bit of a pain, and were changed to two separate mechanisms on later carbs. If like below, it may take a few trial and error adjustments to get right.

P7300020.jpg P7300018.jpg

After the engine is hot, shut down and make sure that "half-moon" shaped cam(where the big slotted screw is), is at it's "off" position, i.e. at it's furthest stop in clockwise direction.

Once that's set, restart and then adjust the idle screw to correct RPM. FYI idle rpm is different for Powerglide Auto vs Manual transmissions so check your owners manual or service manual for the specs.

If not the above type, adjust the choke cover as above, and the idle cam is isolated for easier adjustment. Sorry no pics handy.

Rich

[Zachary H.]

Re: Carburetor issue?

Rich, thanks for the help. My carb is as picture 2 and when I manually rotated the half moon the idle came down to where it should be. It feels very sticky since I had to rotate by hand. Is there a way I can loosen this up? Thanks to all.

Zach

[Richard M.]

Re: Carburetor issue?

Zach,

It could be several things.....

It could be a blocked up internal piston inside the choke. It can get sticky from carbon from a leaky air tube inside the exhaust manifold or improper lubrication. It needs to be dry. no lube of any kind. Here's what it looks like inside when it's apart. You can see the little brass piston. It fits in the small cylinder of the choke housing. Check that it's free to move fully up and fully down.

P7240052.jpg P8310003.jpg P9020031.jpg P9020032.jpg


Or it could just be the choke adjustment(black cap) to richen or lean the cold start. You need to loosen the 3 screws and rotate the cover to get it to the right mixture. If the mixture is right, then you loosen the lock-screw on the upper cam that attaches to the choke butterfly shaft and lock it in appropriately. It's at the top of the 2nd picture in my previous post. There's a procedure for these adjustments in the Chevrolet Service Manuals or Carter Manuals. If you don't have these yet you can browse through here to get some info. http://chevy.oldcarmanualproject.com/

and in particular:

http://chevy.oldcarmanualproject.com/carb/56cfbc/index.html

Page 41 begins the WCFB section and it's adjustments.

Rich

[Zachary H.]

Re: Carburetor issue?

Rich, Thanks for the info and links, very helpful. Upon closer inspection I noticed my carb is missing the bottom of the 3 cap screws. Not sure how long it has been missing. I will find a replacement and get it installed. Not sure what effect if any this has. The cap is tight and can not be rotated. I will run the car and see how she behaves. If I need to get into the choke housing can the cap be removed with the carburetor on the car or does it need to come off?

Zach

[Richard M.]

Re: Carburetor issue?

Zach,

The cap is made to rotate after loosening the screws a bit to adjust the butterfly. That's the "Rich"/"Lean" setting in the adjustment steps. After setting it, just snug up the screws to lock the cap in place. Don't over tighten as the Bakelite plastic is brittle and can break.

Rich