LA 360 high idle

d100clubcab said

Picked it up from rebuilder
Sat dry in the same ziploc back he returned it to me in
Sat in the cab of the truck

Choke/High Idle operation are all the way off
High idle screw was almost taken out it's backed out so far
Truck will only start with choke engaged
no choke, no start

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Any unused port caps missing?
Did you try plugging off a PCV hose if you have one?

I would have to lean towards the carb.
There are times with a dirty carb I have revved the engine holding the throttle open all the way open as I closed the choke almost killed it with the choke by hand.
Once in awhile it'll suck out the stuff causing blockages.

Just revving it and closing the throttle doesn't do the same thing, as all the vacuum is under the throttle plates only pulling on the idle and transition slots.
Revving and choking the crap out of it makes a big vacuum above the plates where the main fuel flow is.

Just something to try that works sometimes. :D