Hey guys, while I'm on a roll maybe you can help me out with this.
I , at best weather , will have the 1949 F5 out 2 times a week in summer for farmers market.
It rains a lot here so doesn't happen. If she sets a couple weeks the gas seems to flow back down the line, or evaporates, and takes a good while pumping and choking to get the gas to carb again.Starts very easy once gas reaches carb. Is there anything I can do to remedy this?

 

Here are 2 things you can do:

You can get a bulb like an outboard motor has and put it in the gas line. You use this to prime the carb before starting it. Not the easiest thing to do on the F5.

You can get a small electric fuel pump and pit it in line where you can't see it. Use a push button to to give it power before you begin cranking to fill the system with gas. I have this on one of my old cars to prime the system. Works a treat.

 

There are check valves in the fuel pump that should prevent any bleed-back to the tank. If you don't have a vented gas cap this will create a vacuum in the tank and possibly pull fuel past the check valves. I have the same issue after sitting for months, but I attribute it to just being a tired old cold-blooded engine. You could try an electric fuel pump downstream of your mechanical pump to see if the problem persists.

 

Keep the gas tank as full as possible. When it's Full, gas will fill the supply line to about 6" below the fuel pump inlet on a V8. Then it has very little air to pump out.

But unless you've replaced or thoroughly cleaned the line from the tank to the pump, you likely have a bunch of crap in the line and it's affecting the check valves in the pump. The line is the low point in the system and all the junk ends up there.