Too Much Advance?
 

In the process of tracking down my stumble/backfire from idle I wanted to check the curve on my D.U.I. distributor...I checked the advance and was surprised at how quick it came in....Im not sure if this might cause my problem or not. Seems like Ive read somewhere where too much advance too quick can cause my problem..



RPM Adv Total

750 0 8
1250 10 18
1500 13.5 21.5
1750 18 26
2000 18 26
2250 18 26
2500 19 27
2750 19 29
3000 24 32

The advance is more than double the stock Tbolt v8-24 at 1250 and 1500rpms. It is double at 1750 and 5.5 degrees more at 2000. It gets closer after that. But Im wondering about the huge difference between 1250 and 1750......Thoughts anyone?

BH

sorry I don't think and have never seen this happen
,,unless its going into detonation ??? good fresh gas ??:D

I run my timing locked in at 38 degrees and know of many others that do the same. I think your problem is more than likely carb related or something else. Some older stock car motors with vacuum advance run a lot of advance at low RPMs with no trouble. Does the stumble happen when you are on the trim button? Just curious. One of my buddies boats had that prob recently and it turned out to be a bad voltage regulator on the alternator. Good luck!!