Thread: Dang SBC won't stop!

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Posted by gherkin:
"I unplug the power lead to the HEI.......It runs"

This is a dead giveaway that it's not alternator feedback, it's hot spots in the chambers and the throttle blades being cracked open a hair at shutdown. It's getting fuel and air from the slightly open blades and ignition from the hot spots.
Fixes:
1. Advance the timing a little.
or
2. Adjust the throttle blades to completely closed. Mount a 70's GM dashpot at the throttle lever so that when the dashpot gets 12v ignition juice, it opens the throttle blades to the idle position, otherwise, without any juice the dashpot is dead and the throttle blades are competely closed. The motor CANNOT run on without fuel and air.
or
3. take a friend and a gallon of water to a secluded area. With your friend on the accelerator to keep the motor revs up, pour the water down the carb throat (not too much or you can hydraulic the motor and break things). Feed it all you can without killing it with your buddy workin' the pedal at about half-throttle. You won't believe the crud that comes out the tailpipe, so be sure and don't do this in a congested (with people) area.
or
4. Shut if off in gear.
or
5. All of the above.