[trevarthan]

UPDATE:

Removed sender. Filter sock was definitely falling apart, but I was dubious that it was enough to block flow. Ordered a new sender.

Went on a vacation out of the country for a week. My new sender had arrived when I got back. Installed it last Thursday, I think. Replaced the two soft lines between the frame rail lines and the tank at the same time.

It still exhibited the same behavior. I knew at this point it was either the hard line or the rubber hose between the pump and the hard line, so I reached down and traced my hand along the rubber hose immediately after a stall. Sure enough, there was a kink in the hose right where it met the hard line.

I had checked this hose previously and it felt and looked fine, so I think what was happening was that it had collapsed internally and as it ran pressure built up, causing it to kink.

Replaced that hose and haven't seen the problem since.

We rebuilt one carb then bought a remanufactured carb when the rebuilt carb didn't do the job. I ended up keeping the remanufactured carb because it came with a nipple on the float vent (my old carb didn't have a nipple, remember). The old carb ran way rich and the new carb ran way lean, according to the spark plugs. The old carb's metering rod arm was adjusted to proper specs and the new carb's metering rod arm was a few millimeters high. So we split the difference and lowered the new carb's metering rod about a millimeter and a half.

After a few days of running successfully I pulled the truck into the garage again and pulled the number 1 spark plug. It looks nearly perfect to me, so I guess we nailed it.

The truck gets much better mileage now.

Did I have to rebuild the carb to fix this intermittent problem? No. Absolutely not. If I had run the vacuum test and fuel pressure test for longer than a minute before I removed the carb I would have found the problem and been able to fix it.

Am I sorry I removed the carb and rebuilt it? Hell no. I loved learning how to do this and the vehicle gets much better mileage now. I'm also now confident that this motor is in pretty good health and will last my son a while longer.

Anyway, thanks to everyone who commented for all the help. Hopefully this saga will help someone else with the same problem identify their problem quickly and resolve it faster than I did.