Help Finally got the new motor in and running. It has a couple hundred miles and a few more hours of running on it. Have been working out the bugs - many more changes to the car than originally planned, all done at once. However, I have a new problem. I was out driving the other evening and it started to run crappy with some intermittent missing. Got it home and discovered that the power wire to the electric choke - 870 Holley - had come loose and was running super rich. Repaired that and now it works fine and the engine started right up. But now it is not running as smoothly and it backfires hard thru the carb if I run the rpm up to 1800-2000 and let the throttle off. Any ideas. Thanks dukec
Sounds like an ingition/timing related problem, double check all your plug wires and connections, be sure the cap and rotor are well seated. Check the advance weights and springs on the distributor to be sure they're lub'd and moving freely. If it's not that then look for a vacuum leak.
Copuld also be the pushrod length being too long after machine work done during the rebuild. This could take most or all valve seating ablilty/clearance away. I always use adjustable pushrods from Smith Brothers on all my Buick engines.
When all else fails go back to the basics. Check or replace all your spark plugs. It's a good possibilty that you have a few of the fouled.
Thanks for the things to check. No vacuum leaks - used carb cleaner around base with no change. Already thought about changing plugs - will do that today. Still running original stock points - this may be the problem. Plan to have Dave build a new hei dist. just haven't done it yet. dukec
