Engine dieseling

So the engine diesels when you shut the truck off. Didnt start doing that until after the weber carb was put on. I pulled the plugs this morning

#1 is lean
#2 is very rich
#3 looks perfect
#4 is lean

Im figuring its timing but anybody else have some thoughts on the subject?

It's usually the timing. I believe that's how I fixed mine. Until you have it timed, just kill it by stalling it.
Also, the timing marks are on the pulley, on the high spot closest to the engine. You may have to clean the pulley off to see em.

My truck dieseled after the webber as well but i didn't think it was the timing. What should it be set to?

bump

Most likely cause:

When running the factory carb these trucks are notorious for running rich which will eventually leave a LOT of carbon build-up on the tops of the pistons. When first changing over to a Weber the engine is suddenly running leaner (in most instances) which will heat the carbon deposits and cause detonation or "dieseling". Timing will help, as will a hotter ignition, but ultimately the carbon has to be burnt off.

I had this problem with my truck when I first installed the Weber, the trick below had it gone after a couple tries. Do so at your own risk (I say this bc some idiot will think its ok to pour in 1/2 gallon of water and call it good) but, you can speed this process with an old post-race trick:

Get the truck up to operating temp, by one means or another hold throttle at approximately 2500-3000 rpm, then DRIP water into carb. You only need a drop or so at a time with, say, at least 10 seconds between drips. Works kinda like a lil pressure washer in the cylinder. This will speed the "cleaning" of the piston tops and valve faces. However, too much can cause some serious problems. And, if you still have a catalytic converter you may not want to try this as it may stop it up. Guaranteed you will blow some sh!t out the exhaust. If you're not comfy using water, I've also heard of WD-40, but I think the water works better.