Engine lags and stalls when initially pressing gas-Solution Found?!

My 67 273 2bbl, did the same thing. Turns out someone had plugged the vacuum line right before the vacuum advance canister. I removed the plug and all is good.

Get a vacuum pump and hook it directly to the vacuum advance can (short hose).

First as you increase vacuum the engine rpm should raise.

Second it should hold vacuum.

Also be sure you have the vacuum hooked up to the correct port on the carb.

Also if you have a green canister device between the advance can and the carb. Temporally bypass it and see if there is any change.

My CAP engine calls for initial advance to be 5 after TDC try 5 before TDC and see how things go.

Lastly with the vacuum advance disconnected does the timing advance as you you increase engine RPM.


All of this assumes the carb is in good shape. You can check you factory service manual for stock jets and rods.