55 650 gas tank building up pressure

I was pulling a disc for about an hour or so then stopped to get something to drink, and shut the tractor off. Then fired it back up and it studdered a little I was pulling a disc for about an hour or so and it was well into the 90's, then stopped to get something to drink and shut the tractor off. Then fired it back up and it shuddered a little bit at first, but then ran good for about a 100 yards and then it stalled out. I tried to start it back up but it turned over but would not fire. So I took a look and saw gas dripping out from around the crab somewhere. In the past if I leave the gas on and let the tractor sit for more than a few hours the carb leaks gas and fills up the rubber pipe that connects to the air intake. So I disconnected the rubber hose and gas poured out, more then I have seen in the past. So I hook the hose back up and try it again and still no luck. Then I took the gas cap off to see if I was out of gas and I blast of gas fumes came out, the tank had quite a bit of pressure built up. Now that the tank had the pressure released I tried to fire the tractor up and still no luck. I then noticed some sediment in the sediment bowl was moving around like gas was flowing trough it even then the tractor was not running. So disconnected the air intake side hose and sure enough gas poured out again. As this point I was out of ideas so I turned off the gas and opened the gas cap. So now I know I need to get a gas cap that is vented, but not sure if I messed something else up in the carb to cause gas to just keep filling up the air intake side.bit at first, but then ran good for about a 100 yards and then it stalled out. I tried to start it back up but it tuned over but would not fire. So I took a look and saw gas dripping out from around the carb somewhere. In the past if I leave the gas on and let the tractor sit for more then a few hours the carb leaks gas and fills up the rubber pipe that connects to the air intake.

You definitely need to get that cap replaced or leave loose. I burnt down my tractor with this exact same scenario!

I didn't realize the cap was a none vented model and when I got here good and hot it stalled. Dummy me I disconnected intake hose that whose full of gas and she went up in flames.

It sounds like you have some dirt on the needle you might need to rebuild the carb. You could try to open the drain in the bottom of carb and let some gas run out while lightly tapping the carb with a screw driver handle.

You should get in the habit of using the fuel shut off because it's normal for them to leak a little bit.

Carb float needle might be stuck open. Doug

The correct Fuel cap you will be looking for from New Holland is part number E5NN9N208CA . Thanks Tony

Got heat shield under tank? Had same prob with carb leak.
One float arm bent hitting side of bowl. Never remove cap
when tractor hot!!

good vented cap like Tony's
and some needle/seat/float work
(might as well clean the whole carb and fix
what needs it when you are in there)

JMHO, but this year in this heat,
where everything combustible is on
the ragged edge of igniting.........
I'd disregard all our normal advice on
checking for a problem right then.
If the tractor has been working hard, and quits.
Turn the gas off and walk away for awhile til it cools some
before working on anything.

thanks for the info guys - -I did pull the carb off before I left the farm and have taken it a part and cleaned it up. Now i am going to rig it up to make sure the float value is shutting of the gas once the bowl is full.

Yes the heat sheild is there under the tank, but I am 99% sure I am running enthol gas, so I will use real gas when I put gas in it.

When I got the tractor the gas cap had a chunk of the rubber gasket missing. Would this allow the tank to vent until I get the new gas cap?

well the test proved that the float was not closing all the way. If I give it a little push on the needle it closed.

Is it ok to bend the floats a bit to put a touch more push on the needle?

ok I bent the float a bit and now it seems to work ok and stops gas from flowing once thw bowl is full. Now I have to hook it back up to the tractor and see if it works

CNH dealer will give a free vented cap to anyone who brings in the old cap and tractors serial number.Got mine over 20 years ago.The first thing I learned was never open the gas cap on a hot tractor.