Backfiring through the carb.

[TulsaSpider]

Well I haven't been real talkative on here lately. That's a good thing. My little car has been doing very well except for a pesky coolant leak I can't find... that is until lately. here's the scoop. I get a backfire through the carb when the car is idling, like at a stoplight, and I begin to give it some gas to let the clutch out and once in a while I will get a backfire through the carb. This the only time it happens, well I tried to start it while ago and it did it 3 times then sputtered to life. Any ideas what's up? It's running really well and there is no missing at any RPM, the idle is smooth and constant. I turned up the idle a bit and that seemed to have helped a little. I checked the timing and it is at 10 BTDC. ???

[racydave]

Since you have points, it might be interesting to use a dwell meter to check the internals of the dizzy. The dwell really should not vary but maybe a few degrees from idle to 2-3,000 RPMs. If it does then so does the ign timing. Its one way to check without spending money just replacing parts anyway... Also any vaccume leaks create a lean condition thats first noticable hesitating off idle, and check to see if the carb is held tightly to the intake. Still got the Orange Cat?

[TulsaSpider]

Well I am going to change over to a Fiat electronic ignition. Going to order the new innards tomorrow. Maybe that will take care of it? I'll check the carb too. No the kids took that little one home with them. : )

[So Cal Mark]

checking dwell and vacuum leaks are always good suggestions, but either will affect the way the engine runs at all times. Your problem sounds like it's related to the accelerator pump. The diaphragm could be weak, or the pump nozzle o-ring could be leaking, allowing fuel to go around the nozzle rather than through it