stvaughn

1960/230hp/4 speed. The WCFB was junk and I had a Edlebrock 1406 on the shelf so I purchased a Mr. Gasket adapter and put the 1406 on. The engine runs fine, however, with the engine running the gas pedal is difficult to initially push down usually resulting in the engine speed running up way beyond what is necessary to get rolling. With the engine off, no problem, everything works smooth. The linkage moves freely and the return spring pressure is not excessive. In fact I can reduce the pressure to nothing and with the engine running the carb is still hard to operate.

There is a SIGNIFICANT increase in the pressure required to operate the gas pedal with the engine running compared to the pressure required to operate it with the engine off. The difficulty is in the initial movement of the gas pedal. Once past the initial movement everything is smooth. I've tried reducing spring pressure but the carb won't return to idle without enough spring pressure. I've replace the gas pedal and all the throttle lever parts. I'm convinced that the problem is at the carburetor but don't know why or how to fix it.

Steve

Tampa Jerry

Is it possible that your motor mounts are no good? Jerry

hope2

disconnect the linkage at the carb to prove it's the carb.

stvaughn

Motor mounts are brand new.

Have disconnected the linkage and it is definitely a carburetor throttle shaft problem. (but only when the engine is running, moves freely when engine is not running)

Steve

Bluestripe67

Is there any gasket material between the carb/adapter/manifold that is close to the throttle blades and could move under suction/air flow from the engine. It's a stretch thought. Dennis

Frankie the Fink

The difference between the engine not running and running (at idle) is high vacuum. Something in that carb that is dependent on vacuum is hanging up. IMO rebuild the WCFB and junk that Edlebrock. I have 6 WCFBs and they all run great...

With linkage disconnected and engine idling take a long screwdriver/Popsicle stick/wooden paint stir stick and carefully push down through the throttle bore and see how hard it is to open the primary plate.... If that is binding then maybe the plate is hanging up on the intake manifold or gasket due to engine vacuum or expansion from the heat of the running motor.

Make sure your accelerator pump is working freely with the car idling too.

KC John

I agree with FTF, check the accelerator pump. Disconnect the linkage from the acc. pump so just the plunger is sticking up in the air. then see if the throttle feels like it sticks. I had this problem with my 1406 and as soon as I pulled the linkage all was well.

I found out by fooling around with my carb one day seeing if I could tune it a little better. I moved the linkage to another hole and as soon as I did the carb started to bind. I guess the plunger was worn a certain way and changing the leverage caused it to bind.

stvaughn

KCJ,

Disconnected the pump, it didn't help. While I was sitting in the car I tried this: with the motor running I applied pressure to the gas pedal, not enough to overcome the resistance but just to where I felt like it was at the edge, then I shut off the motor and the resistance went away and my foot moved the gas pedal. I did it three times with and without the accelerator pump hooked up with the same result each time.

I'll try FtF's suggestion tomorrow when I am more alert. I've been fiddling with this all summer and it's got me bumfuzzled.

Frankie, my WCFB has been "bubbized" by some unknown previous owner. Secondary float ruptured and the needle valve soldered shut. The "repair" didn't work and when I got it gas was pouring straight into the manifold. Previous owner complained of strong fuel smell and poor mileage. Wonder why? Anyway If I have to spend money to replace my Edelbrock I may go ahead and get a WCFB and that will bring up a question for another post.

Steve

Frankie the Fink

OK - this IS a weird problem.

So I'm stumped, particularly if your WCFB linkage worked OK. You've eliminated the linkage and motor mounts IMO in post #4 above. Unless heat or vacuum is making your throttle plate stick in the bores only when the engine is running and they are fully closed I'm out of gas (no pun intended) on this one.

BTW Bob Kunz or Ron at www.daytonaparts.com can fix nearly any problem on a WCFB that you can imagine.

plaidside

This is a real head scratcher!
I would turn up the idle speed by turning the idle screw 1/2 turn CW and see if this makes any difference.
My theory is if the throttle plates are sticking in the bore and under high vacuum it is increasing the force needed to open the throttle.
You stated this carburetor was "bubbized", so anything is possible. Maybe you have the wrong size throttle plates in the base.
It happened to me on one of my carbs on my 2 x 4 set up.
The front carburetor had primary plates that were .030" larger than stock and it wasn't allowing the plates to close enough, which caused my two front plugs to foul after a short time, due to the fact the transfer slots were exposed all the time.
Joe

Frankie the Fink

I think his WCFB was bubba-ed Joe - he is running with an Edelbrock he had spare (could be bubba-ed too -- he doesn't say).

hope2

alignment of butterflies? loosen the four screws holding the butterflies to the shaft, naturally with carb off, let them seat against the bores. or, too much play in shaft.

Pop Chevy

I'll bet the leverage point is diff between the 2 carbs, can you try a diff hole for the linkage ?

Frankie the Fink

Folks need to read the whole post....he has the problem with the carb on the car, engine running and NO linkage attached...

I can't say too much - I have a Carter AFB on my '63 that will not return to idle consistently unless I stab the gas pedal sharply -- works fine off the car. And I've checked all the suggestions given above. I'm gonna swap it off for the original WCFB and just hope the issue "goes away"...

AZDoug

Edit:I am leaving this post up as others may need the info, but I see you already changed the gas pedal, re reading your post.

Original post:

Get a new gas pedal.

Look at your old pedal, there is probably a divot in the backside where the rod contacts.

the rod falls into the hole, and it hard to get out.

Changing the carb probably re aligned the rod so it fell into the old wear hole.

Doug

waltonb123

I had the same issue and my gas pedal had a divot. I replaced the pedal and all seemed fine for a few months, then it started again. What I found is that there is a real fine line when adjusting the linkage trying to get full throttle, the angle creates a binding situation on the plastic tab on the back of the pedal. Just adjust in 1 turn at a time until it frees up.

stvaughn

Waltonb,

I had considered the adjustment issue at first but as stated earlier the problem is in the carburetor because I have the sticky throttle issue with the linkage disconnected and the motor running but not when it is stopped. I did some adjusting on the carb today and may have helped the problem. Driving some will tell. Now another post started on timing.

I know I have checked the throttle plate clearance with the adapter but I wonder if just having this adapter with its offset and coned shaped bores is causing some kind of binding issue when sucking air.

One thing I have learned tinkering on these old jalopy's through the years is that there is always more to learn.

I appreciate everyone's help. This is a head scratcher for me.

Steve