Quote Originally Posted by Farrar View Post
I decided to fire up the engine and tune the idle mixture: I set the screws out 1.75 turns as a cursory "enough to get started" position, then cranked.
Base setting for a 2150 is 1.50 turns out...

Quote Originally Posted by Farrar View Post
"enough to get started" position, then cranked.

And cranked.

And cranked.
If it starts and instantly dies, it could be the mixture screw settings. But since it just cranks and cranks, I'd suggest you look elsewhere... Whether they are all the way in or all but removed, it should fire off. (The setting has virtually nothing to do with cranking or running when off idle.)

Quote Originally Posted by Farrar View Post
By now I figured the engine was flooded, so I propped the choke plate open with a 3/8" drill bit and cranked again..
The engine must be warm when setting the screws, so the choke should have been fully open...

=======

I agree it is probably flooded now...Pull a few of the easy to get to plugs and see what they look like. If they look OK, look for a vacuum leak. (Possibly cross-wired?).