392 Hessitation

wiggins

wiggins

Member
I have my 69' Travelall running but not to great. All original equipment, 98,000 original miles on truck. Its a little hard to crank from cold but it sits and idles great. I have set the points at 0.017, gapped the plugs, set the timming at tdc. The problem other than the hard start(have to crank on it awhile) is that it cuts out upon acceleration from a stop. At normal accelraton it does this but if I put my foot to it it just gets up and goes.I have moved the timming fron tdc to about 6 adv and it has not fixed anything. Even just set it by ear and the problem has persisted so I am know assuming its is in the carb? The motor is fresh(71 miles) and everything is new except for the carb and the distributer. Any help is appreciated, thanks wiggins

also the carb is a holly as well as the dist. But I am at work and do not remeber the mdls right now
 
Last edited:
Very likely that your carb needs a complete overhaul if all ignition components are in spec and the carb service has not been performed since cowboy ronny was potus. Mike mayben recommends carb reconditioning every 2 or 3 years now that alkygazz is pretty much everywhere.
 
Thanks but any idea what is the culprit on the carb. It runs at idle real smooth and runs up and down the road good. I just cant accelerate w/o babying the throttle. Another words if I accelerate at normal speed it will choke down and die. If I baby it it still chokes down bit I can keep it running and if I punch the pedal the tires sqeak and off we go w no hessitation.
 
I'd have to say you have a non-functional accelerator pump system.

If it's a 392, it should be equipped with some variation of the Holley 4150 or 4160 carb. They both use the same type accelerator pump but it May be two different versions regarding the internal check valve. One has a hanging ball. The later version uses an orange silicone rubber check valve. Both use the same 30cc accelerator pump element.

Pull the air cleaner. Then watch down the venturis while you pump the throttle lever a time or two. Each time you activate the throttle lever, you should see a strong squirt of liquid fuel from both of the accel shooter outlets (n=2). If weak or no fuel shot, the accel pump system needs to rebuilt.
 
Just like I said before. Internal components are either out of spec or gummed up. A refurbish is the best way to restore faulty carb performance. That involves tearing it down completely, soaking the hard parts in tyme soak as per directions, and installing a proper refresh kit. The list number on the airhorn will provide proper carb id. If this is a Holley modular carb, you want to get a Holley brand kit. Save all your old gaskets for exact matching with the new gaskets as these kits tend to be a one size fits all deal and the fit isn't always perfect for every single carb application in existence. Some hole poking in the new gaskets May be required. There really is no other magic bullet approach for an old carb that needs luvin'. The shortcut is the shortcut.
 
May send it to you tues. I really wanted to drive this rig to my family reunion w the kids over at lake buchanan at the end of the month but that about a 6 hr trip and I would rather have it running properly since my kiddos are coming w me. Roughly how much and were do I send it?
 
Ok mr mayben I finally got a chance to look at that carb. Under a fast pull of the throttle everything looked fine, but under a slower steady pull back of the throttle it pumps out no gas for the first 1/4 or so pull then it squirts the gas out.
 
Two things to do...

1) remove the primary (front) fuel bowl and rebuild the accelerator pump system. It's very simple to do.

2) remove the accel pump shooter from the main body (upper and lower tiny seal washers are involved). Then remove the check valve from the accel pump hole and blow air through the system to insure it's clean and flowing.

Once the carb is reassembled, then open the throttle fully and verify that you have between 0.015" and 0.030" of free additional travel in the diaphragm. Adjust by manipulating the screw retained with the locknut.
 
You must log in or register to reply here.
Back
Top