I've got 25,000 miles on this 302 carb build. Tonight I ran it hard, no more than usual, and as I was decelerating, I felt/heard a change in the exhaust note. By the time I came back down to idle, I could feel the motor kind of "chug" like it was missing. It idles like crap compared to before and stutters a little bit, a very little bit, off the line. At wide open throttle it runs great, but as soon as I take my foot of the gas I can hear it run likes it's missing or something; there's definitely a lot more vibration here. Under steady pedal I can feel a small surge come and go. I yanked the plugs and they're awfully white. The carb seemed to be running a little rich before. On my agenda is the fuel filter, intake leaks.... I checked the vac. lines and one rubber cap was busted, but fixing that did nothing for the motor. Any other ideas? Motor info: 306, roller 600 holley vac 2ndary pertronix in a stock dizzy/40k volt coil
was any of the plugs wet..... Sounds like a broken spring.... That or the power valve in the carb took a dump.... When you accelerate does it just fall on its face?
vibration... might suggest as noted above a valvetrain issue somewhere. No vacumn leaks or problems , right? make sure fuel and ignition are correct then go to mechaincal area like the valvesprings, etc.
Sounds like a piece of trash or water found it's way into the carb.It's not the power valve, it would be dumping fuel into the carb if it was, and with the plugs running white, it's obviously leaned out.
I had that same feeling in a 77 f-100 I had right before the motor let go. burnt a hole in a piston. Guess the hole was small at first and got big pretty fast. It didn't last long aftr it felt like that though. Hope it is something easier than that Bruce.
Definitely do a compression check.that broken vacuum fitting plug was causing the car to lean out(sucking too much air where it shouldnt) and may have burnt a valve/piston.Good luck.
Well, here's my day: Changed the plugs and checked the timing: no change Clean the cap and rotor off: no change Started checking each plug wire with the light and found some dead spots New wires cap, and rotor: runs great I'll be keeping an eye on the plugs.
