Help engine problems

[Donw]

have a 1969 corvette 350/300 4 speed. When In start it, it has a hard time running and it continuosly makes popping noises out the exhaustand carburator.

Anybody have any ideas what it might be? I tried playing with timing and points not with meter just seeing if it would stop. (NO LucK) I am afraid it is a rocker arm or flat cam but just doesn't sound that way. (could be wrong).

Could points or timing etc. be it or the latter.

Any help sure would be appreciated.

PS It is the original Rochester 4 barrel just rebuilt. Good shape.

Thanks

DonW

 

[waterboy1976]

something in the ignition....Distibutor? points? plug wires on right?

 

[JohnZ]

See my response to your identical post on the other forum.

 

[corvettespecialists]

It could be the timing, causing the popping. It could also be the carb (even though it was just rebuilt) dumping gas. If the rear two barrels are getting gas when the car is at idle, it needs to be rebuilt with the float levels adjusted down. Check all the vacuum hoses to make sure they are attached in the correct place. Also, there is an air injection hose assembly that comes from the air pump and goes into the exhaust manifolds. If you cap off the lines, that may stop the popping as well. They do have to be functional if your car gets tested for emissions.

 

[Mike Zarnock]

Popping back through the carb usually indicates a bad intake valve. Popping out the exhaust is usually an ignition problem. Having it happen at both ends seems to be a total timing problem. The distributor could be a tooth off, dwell could be off, a bad condenser. There is an explosion at the wrong time, that is why it's popping out of where ever it can.
Does it skip at idle, under a load, or when revved?
To check the dwell without a meter. Run it at idle and close the points slowly until it starts to falter, then back it out 1/4 turn. You should be very close.
Good luck.
Mike

 

[cheftl13]

Popping from carb

It sounds like you have a vaccum line problem! If you getting popping out of your exhaust, that is timing usually, Out of the carb usually means one of the vaccum lines going to the carb is on wrong or broken. I had the same problem. I put a brand new carb on and was getting major popping out of the carb. Air mixture was way off. So I un-did all of the lines, and put them back on securely, and whalla! Perfect.