F engine is being a real f'er

[jimmclarty]

Hey guys,

I got a 1970 40 out of a field a while back and finally got most of the spark stuff sorted. Finally got it to start and it spit out a lot of smoke (probably from sitting for so many years) and then it would only stay running if I pump the gas. Then, it just dies after about 5 seconds.

I'm pouring gas into the carb as the gas tank is probably gunked. I'm guessing this is a carb issue or it's just not getting enough gas to keep it going. But, I really don't know.

Can anybody help me out?

Thanks.

 

[bhsdriller]

I'd check the condition of the tank first....maybe a flush and good cleaning if not most of the time it'll need replacing.

Stock mechanical Fuel pump, working ok? You can test it easily

Any fuel filters in-line?

 

[jimmclarty]

I'd check the condition of the tank first....maybe a flush and good cleaning if not most of the time it'll need replacing.

Stock mechanical Fuel pump, working ok? You can test it easily

Any fuel filters in-line?

I think it’s the pump. How do I test it? Thanks.

 

[bhsdriller]

I can't find it for some reason but i think it was a volume test. You undo the line at the carb and place it in a catch can. While cranking you measure how much it pushes out over a certain amount of time

 

[thebigredrocker]

As you guessed with the filter change, it is a fuel delivery problem.

You may have more dirt and/or rust in the tank than a new filter can handle. Remove the line at the filter and measure how long it takes for a cup of gas to run out. Then blow compressed air back in to the tank and repeat the test. If blowing it out increases the flow, you have junk in your tank.

If no junk in the tank, remove the gas line at the carb and measure how much time it takes to pump a cup of gas. It should pump a cup in less than 1 minute of cranking with the ignition HV wire disconnected. If the pump isn't putting out, you may need a new one, but they usually leak when they fail.

 

[jimmclarty]

I can't find it for some reason but i think it was a volume test. You undo the line at the carb and place it in a catch can. While cranking you measure how much it pushes out over a certain amount of time

Ok. I’ll try it. Thanks.