FINALLY - Vacuum Advance Dilemma Solved

[TButtrick]

Thanks for posting that article! I've been running ported vac on my 650DP forever. Been hunting down a dieseling problem (run-on) which forced me to look at all the base line settings once again. Eliminated any possible vac leaks (new intake and carb gaskets, PCV and lines, etc.) Glad I suspected the intake gaskets first. They were FelPro 1250s whose coolant ports had disintegrated in just 2000 miles. (common problem with these) New dizzy and set base and total timing to 12 degrees base and 34 total all in at 2900rpm. I have a new Quick Fuel 650DP with annular boosters. Idle airs are 1 1/8 turn out (just below max manifold vac) Pri jets are 70 and 76 for secondaries on a 392W with AFR185 heads. Dieseling is all but gone as I've run some octane booster and CRC carbon cleaner through a tank and slurped through the manifold intake to help clean out any carbon build up. New AutoLite 3924s gapped at .045". Still feel like I'm on the edge of dieseling as it coughs from time to time but mostly after a long cruise and MUCH better than before. Maybe full manifold vac advance to the dizzy will help carbon build up and fuel mileage. As of right now, fuel mileage seems to REALLY suck when just cruising.