4020 leans out when hot, vapor lock?

[mrjata]

Tried to start it tonight when it was cold, wouldn't run without the choke, wouldn't excelorate with the choke on, Drained all the fuel will blow out lines tomorrow and get known good fuel to replace. Fingers crossed. Oh moved the fuel line out away from the block about 1/2" too.

 

[ss55]

Haven't checked fuel pressure, but if it was low it wouldn't run much at all, even with the choke pulled. All things are pointing to percolation or vapor lock. Might get the lift pump to be safe, not expensive at all. But All states ag shows 2. wonder what the difference is?? One looks like two cylindrical pumps the other looks like a traditional fuel pump more of one large dome, much like the glass bowls that used to be there. Any thoughts on those??

The glass dome pump was original equipment on those tractors. Back in the 1970s dad had the dealer out for a service call when his 4020 gas acted like yours is late one afternoon under the corn picker. Serviceman had the metal pump along, installed it and the problem was fixed. The glass dome will let you see any water in your fuel, otherwise the two pumps are used interchangeably.

Next time the problem occurs, try adding more fuel to the fuel tank, if it runs better the lift pump is probably bad. Checking fuel pressure is a quicker way to test the same thing. Also listen for a strong vacuum when removing the fuel cap (plugged vent).

 

[ss55]

Tried to start it tonight when it was cold, wouldn't run without the choke, wouldn't excelorate with the choke on, Drained all the fuel will blow out lines tomorrow and get known good fuel to replace. Fingers crossed. Oh moved the fuel line out away from the block about 1/2" too.

If it still won't run without choke tomorrow morning, try filling the fuel tank and then try starting it again.