Hello, I recently posted a thread and thought I had found the problem but was wrong. I have an 81 f100. Here are some details:

1. Truck had been sitting for 4 months (stabilizer added).
2. After a little priming I was able to get the truck started.
3. About a week later I tried to start it again and it would die after a few seconds.
4. I disconnnected the fuel line just before the pump and attached it to a cup of new gas. It started right up, held idle, and worked great.
5. I added about 9 gallons of fresh fuel to the tank. I had to prime the system in the same was as before with the cup for a few minutes, but then after reconnecting the fuel line it ran well from the tank.
6. It's now the next day and I am back to the same problem. When I first start it up it sounds great and then just suddenly dies.
7. If I attempt to restart it again and again it seems to get more difficult each time and requiring a lot of pumping action.

It's so sudden that my first thought was a carb problem but nixed that as an option because simply replacing the source of the fuel solves the problem.

My thoughts now point to insufficient gas getting to the carb, but if that was true why would it start so well to begin with and then just dye...unless perhaps it was just running off what was in the system from the pump to the carb.

Another thought is if the fuel system was losing it's vacuum from the pump to the tank and causing the fuel to recede back into the tank..wouldn't I just get nothing when trying to start truck. It's almost as if enough fuel is there initially to start it up but then disappears. As you can tell I am completely perplexed and would really appreciate any suggestions.

P.S. My truck is loaded with crap sitting in the yard of my house. I am trying my best to avoid looking WT (white trash) and would love to get this thing fixed for good.

Thanks

 

You sure you don't have a float stuck and you're actually loading up with too much fuel? After it's been sitting all the pressure has bled off the line and so it doesn't over fuel until the bowls are chucked full again.

 

I first thought it was a carb related issue also but if the problem can be eliminated simply by bypassing the tank I've got to think it's something else. I will say though that the manner in which it just stops is very similar to a carb issue.

 

how about the fine filter on pickup in tank

 

If it runs then dies, it may be that it is running off the gas in the float bowl and the fuel line has a leak. Once you prime it it runs. Check the connections at the fuel pump and the rubber connections in the line for any leaks.

 

I would disconnect right at the carb, to be sure of the amount of gas getting that far & also that it's getting through any in-line filter you might have on the carb.
If you have a continuous good flow, then quality might be the problem - even with the 9 fresh gals. added.