1971 C10 L6 4.1L coughs after turning off

[trevarthan]

Hello,

I bought this truck a few months ago. Sometimes, when I turn the key off, the engine spins down, then "coughs" and tries to turn over one last time. The previous owner thought this was a malfunctioning carb, so the truck came with a carb rebuild kit.

I've since replaced the door locks, axle bearings, brakes, turn signal switch, fuel pump, power steering pump, radiator cap, and even the air filter. I think it's pretty funny that he prioritized this minor issue as a must-fix-first thing, but he's an old school engine racing guy, so I guess that makes sense.

Is this a carb issue? Will a rebuild kit fix it? Is there a book I could buy that would teach me how to install the rebuild kit? I replaced a head gasket once on a 94 toyota pickup, so I'm pretty sure I'm handy enough to handle it. I just need instructions.

Alternatively, Autozone sells an automatic choke carb for about $250. I assume this is an auto choke carb since I don't see a control anywhere for the choke, and under the air filter there was a little doo-hickey labeled "AC". It must not be working though, because I have to gas it for 30 seconds when I start it to keep it running.

Any info appreciated. I'm having a lot of fun bringing the mechanicals on this thing back to working order.

Thanks!

[geezer#99]

It's called deiseling.
Turn down your idle or pull back your timing a couple degrees.

[RManson]

Sounds like a timing issue.

If it's an Auto trans truck, you can shut it off in 'drive' so as to avoid embarrassment when you pull up to the local car hop.

[trevarthan]

It's a three on the tree. I just hold the clutch down until I'm sure it's done. I'll check the timing and idle for sure. Thanks.