te 20?

tractor starts an shuts off after a few seconds,gas is on an its new gas.

Float stuck? Got a bubble in there? The line or filter?

Like Tony says. Sounds like a plug somewhere and it leaks through slowly and fills carb bowl when it sits a few minutes, and when the
bowl gas is gone it shuts off because not enough is coming through the line to replenish the bowl. Block could be anywhere, including
tank.

(quoted from post at 08:12:21 10/10/15) Like Tony says. Sounds like a plug somewhere and it leaks through slowly and fills carb bowl when it sits a few minutes, and when the
bowl gas is gone it shuts off because not enough is coming through the line to replenish the bowl. Block could be anywhere, including
tank.

Click to expand...

Where should I start to try too fix the problem?

(quoted from post at 08:12:21 10/10/15) Like Tony says. Sounds like a plug somewhere and it leaks through slowly and fills carb bowl when it sits a few minutes, and when the
bowl gas is gone it shuts off because not enough is coming through the line to replenish the bowl. Block could be anywhere, including
tank.

Click to expand...

Where should I start to try too fix the problem?

Next time you have it running and it starts to falter pull the choke out . If it improves , even for a moment it really is a fuel issue .
There are filters in the tanks of TE20 English built tractors . Two in a TED, petrol/ Kerosene , one in a TEA ,petrol . These are upright bronze mesh filters that are fitted to the inlet of the fuel tap within the tank . They are also a GIANT pita . Usually they corrode and disintegrate into a thousand pieces floating about and blocking everything they can .
The fix is to remove the fuel tap , discard anything left of the filter units , flush the tap, tank and lines and reinstall .
Next , remove the bronze mesh filter in the fuel bowl and clean that , use compressed air , they sometimes glaze over with a transparent glaze that looks like wet fuel . Replace this and fit the bowl loosely , turn on the fuel and wait until the bowl fills and starts to leak at the gasket . Tighten up once the bowl is full . Otherwise if it still happens belt the side of the carb float chamber with a plastic screwdriver handle when it starts to stall , the float may be jamming a little , don't hit it too hard , remember it is only alloy .

I'd start at carb, pull plug from bottom and see if gas pours out or just slow drip. Then move up, each connection, each part of the
line, sediment bowl, to tank. As mentioned, particles can float free and clog anywhere. Start at one end and move through the line
until you find it. It can be messy, gas dripping and spilling. A job best done outside.