carsoneschmann

Hey everybody. So I'm new to this forum and having serious problems with my ignition/timing. I have a 1968 coupe with a 1988 5.0 HO that has been swithched over to carbureted. I just installed a new MSD Distributor, Ignition, and Coil. Now the engine will not run under load. At idle, everything is smooth and sounds great. In neutral with a little bit of gas I get a backfire through the intake. However, at high rpm, still in neutral, the engine sounds great. I've checked the plug order 20 times and I know that the HO uses the different plug order. Changes in timing do not seem to fix the problem. I have checked the spark and cleaned and regapped all of the plugs. I have also installed the lighter advance springs. All of this seemed to help, but the problem persists and the car is not driveable. I have also checked all of the wiring and the connections are good. There are no sparks visible anywhere. I checked with the lights off. Anybody got any ideas?

mattdel

Doesn't sound spark related to me at all, sounds like a carb jetting issue.

carsoneschmann

would the jetting be a problem considering that i havent changed it since the old distributor and the car has just been sitting? im thinkiing maybe fuel filter or fuel pressure now.

mattdel

Oh yeah. Carbs that sit = gummed up jets & dried out seals. Any carb that has been sitting (with or without gas in it) for more than a year, I rebuild without even attempting to fire it up. Don't forget, gasoline has a shelf life of about 5 months, after that it begins to thicken and lose octane. Long enough, it can become thicker than oil. It takes quite a bit of contamination to get to that point, but it's possible.