TheSamba.com :: View topic - run-on

Mon Oct 07, 2002 9:56 am

Does anyone know what would cause my 78 to run-on after I shut it off. I have checked the timing, adjusted the richness of the carb, and I don't think it is running real hot. It only happens occasionaly. A freind said that it could be because the engine (which I rebuilt recently) is still tight and rebounds when it is shut off. This problem is driving me nute
I have a 2L with a weber prog. (yes I know it is not popular) and stock dist.
Help!!
Thanks!

Mon Oct 07, 2002 11:26 am

I have the same problem with my 74. I turn the car off and it will sputter a second or two. This only occurs once in awhile. It seems that if I sit for a few seconds after I park and let the engine idle it occurs less frequently.

Mon Oct 07, 2002 11:33 am

This used to happen to my Grandfather's 64 Chevy 6 CYL. As I understand it - it's from Unburned fuel being either in the Exhaust or in the Intake. What happens - is that the fuel gets sucked into the chamber - and causes the car to keep running VIA the Diesel effect (Compression and heat causing fuel to ignite). I'd check my fuel settings, make certain that the car isnt running rich.

Ryan

Tue Oct 08, 2002 7:34 am

You're right, when I let the car idle for a second, the sputtering happens less often. I wonder if, due to the long intake runners of the weber prog, if fuel can condense on the sides when it loses speed and runs into the head? Leaning out the mixture does not seem to effect it. Could it be that the dist has not "un-advanced" and allows the engine to fire? I dunno!!!

Tue Oct 08, 2002 7:36 am

the fuel cut off switch is probably not hooked up/operating correctly. this is the swithc that cuts off the fuel supply when you switch off the ignition. it is desighned specifically to stop the "run on"
lc

Tue Oct 08, 2002 11:02 am

Where would the cut off switch be located? On my bug (stock carb.) it has a wire going to it on the side of the carb. On the weber prog. there is no place for a wire. The only wire is for the elec. choke.

Fri Oct 11, 2002 5:07 pm

they must not have a fuel cutoff. i just assumed they would have used the same concept.
lc

Sun Oct 13, 2002 8:32 am

No Progressives do not have a fuel cut-off... timing could be a tad advanced or as you say you may be shutting down when engine is still revved up a bit.... thats why if letting it idle down for a few secs it doens't do it (as bad) Still make sure you have the carb adjusted right and the point's/ timing ect correct...