Poor Running After Rebuild
 

Engine started right up following a rebuild. Followed recommended break in procedure by holding about 3000 rpm for 3-4 minutes. Engine ran OK except for a backfire or two. Shut the engine down immediatly after.

Today I restarted the engine for the first time since breakin, again it started up fine and idled smooth. The timing was close enough for a test drive. By the time I made it down the driveway the engne was running very rough and had almost no power.

So far I have verified the spark plug wire engagement, fireing order, searched for disconnected vacuum lines. Interestingly, when the distrubutor vacum line was disonnected for the timing it had no effect on idle, maybe even sped up a bit. The gas is 6-7 months old.

Any thoughts on what to look for next? Thanks.

Check for loose distibutor clamp. If the clamp was loose the dist will always go with rotation, serverely retarding ign timing. It would be the first thing to check. Also fresh fuel should be in the tank. 6-7 months is a long time.

Ditto on the timing. When I started my 81 SC after the rebuild in ran crappy. Out of an abundance of caution, I took half the engine apart and rechecked everything, cam timing, valve timing, chains and tentionsers . .. everything was fine, but the timing was way off.

Retimed it to TDC and it purrs. Amazing how timing being off just a little will make it sound like it is falling apart.