I had my '71 302 Mav running very nice recently, but I just went to lunch and the car suddenly felt like it is bogged down and it's idling very rough. The exhaust note at idle sounds odd now too. It will barely accelerate to anything over 30mph and it sounds like the cylinders are all dead when I try to step on the gas...it just completely bogs down. No backfiring thru the carb or tailpipe, vacuum is a steady 18lbs at idle, timing seems good, checked vac. advance and it seems to be working right, replaced coil with spare to see if that was the problem but it wasn't, new plugs+wires+dist+rotor, motor recently rebuilt along with heads/valves, looks like plenty of fuel is getting to carb and both sprayers working good from the accelerator pump, using Pertronix Ignitor III ignition but if it was bad shouldn't run at all right?...ran out of time to look into more. Any ideas? I don't want to be stuck at work or have to call my wife and have her drag my 4 little ones out to come pick me up. I don't think/dont' want to try to make it 40 miles home. Please help!!!!! Jory
What kind of carb do you have and is it new or old? If you start the car and rev the engine in park does it bog down or only under load?
Dumb idea but if you have a tachometer...recently when I accelerated a wire would touch my tach and ground it to kill my coil. Just some odd thing to check. Check fuel pressure? Also maybe a float is screwing up?
It's the stock Autolite 2100 2bbl carb...recently rebuilt. It seems like the problem is mainly only under load but the rough idle does carry over to the higher rpms. This just sprung out of nowhere. Ran great this morning.
Have you tried adjusting the air idle mixture screws? I had a 2150 that I rebuilt that had a similar issue. I could only get up to 50MPH before it died. It acted like it was starving for gas and ended up having a problem with the linkage that runs through the base of the carb and attaches to the butterflies. I ended up having to buy a new carb to fix my problem. I would check the air mixture screws and inspect the throttle linkage area to see if its getting stuck and not closing back correctly.
Choke stuck shut...Needle/seat stuck or debris holding it open...Cracked dist cap... I allmost forgot!!!...Plugged fuel filter...
Mine stayed around 4 at idle and when hitting the gas it would go to about 6-7. Im not sure if thats normal or not.
If the car ran that badly due to an alt not charging...It wouldnt start a second time due to a dead battery...
The problem only started about 2-3 minutes before parking it and then drove maybe 1 minute more to my work. I remember a somewhat similar problem with my '67 Mustang that was the alternator going out...it would only run at certain rpms and had NO power. I don't think my battery would be dead yet but if it is the alternator...it won't be long if I try to drive it anywhere.
Sounds like trash in the filter, plugging it up, or in the needle and seat. Those are what I would check first. Also, check vacuum lines and see if the battery is good. Hope this helps,
Unless you or a previous owner has been into the wireing substantially...I think you have a fuel delivery problem...not saying it isnt electrical related but i doubt it at this point...You can allways check the charging system and be certain the voltage output is as it should be...And the alt belt is tight...
