Need advise on filling fuel system. Blew fuel line back to tank, cleaned tank, refilled tank, vac tank empty. Will the vac tank fill itself when cranking engine or do I need to prime the vac tank to get it to start sucking? If so what is the easiest way to do this? Thank you guys again, Happy New Years!

You can pull the small plug, or the vent connection, out of the top of the vacuum tank and use a small funnel like you use to fill a Coleman lantern with, to fill it with fuel, my 28 vacuum tank holds a bit less than a quart. That should be enough to run the engine for several minutes. I would also add a can of Sea Foam to the full 10 gallons in the main tank, to help stabilize the fuel and, I think that, it helps keep the innards of the vacuum tank working.
That is one reason I mounted a 6 volt AC fuel pump back at the main tank with a mom on switch to be sure the vacuum tank is full before starting the engine after it has set for the winter, etc.

Thank you!

There's a lot of discussion in previous threads about the pros and cons of electric fuel pumps. On my 2 old Chevys, I decided to keep the vacuum tank systems with no electric pump.

To get my '28 AB truck to fire up after putting in the vacuum tank, I installed a 1/8" T connection at the gas inlet to the vacuum tank. One side of the T faces straight up and has a plug that I can remove to pour gas in. Instead of a small funnel, I added a short hose to the cap of a small plastic Coke bottle. Fill the bottle half way and squirt it into the vacuum tank.

This way, you can take the Coke bottle with you and use it to prime the vacuum tank if needed.

When my engine started (nine days ago), it was the first time it ran in over 60 years!! Very exciting. ;-)

Cheers, Dean