8N carburetor leaks gas with shutoff valve open a 1/2 turn for starting and tractor won’t start. Any suggestions??

[kensikora1]

8N carburetor leaks fuel with shutoff valve 1/2 turn open and tractor won’t start. Any suggestions?

 

[Mudrig150]

More than likely your float is sunk or the needle valve has some junk keeping it from fully seating.

 

[pomester]

deleted

 

[Ray,IN]

Gas running from carb = carb flooded due to internal damage.

 

[used red MN]

Gas running from carb = carb flooded due to internal damage.

Very intuitive! but I would go with “internal malfunction” you can’t expound any? Mudrig in reply 2 lists a couple possibilities, I’ll add poorly machined float needle seating surface, float rubbing on side of carb bowl not letting it raise to shut off fuel, float hinge pin binding or installed improperly, float needle positive opening spring clip binding and causing float to bind and not close the float needle. To be honest Mud’s second choice probably is the real problem over 80 percent of the time. Dirt/crud not letting it seat properly, one of my pet peeves is those who use Teflon tape on fuel line connections, remnants of that stuff really love to find there way into the space between the float needle and its seat.

 

[soaked]

Yep, I've found a shred of teflon tape holding the needle open.
Crankcase dipstick smelled of gas.

The shut off valve should turn the gas all the way off, and the carb needle and seat should too.
Shut off valves get sediment build up, and need maintenance, maybe every 7-10 years.
Blue line is main fuel path, and red is reserve. Sealing happens on the end.

Suggest get some pipe fittings and test for leaks before installing like this. Paper towel or toilet paper make small leaks more visable. See pic below


Can test carb for leaks with top half upside-down, like this. Tap fits the float seat, whose threads can leak if not fully tightened against the crush washer/gasket. See second pic below

 

[kensikora1]

Very intuitive! but I would go with “internal malfunction” you can’t expound any? Mudrig in reply 2 lists a couple possibilities, I’ll add poorly machined float needle seating surface, float rubbing on side of carb bowl not letting it raise to shut off fuel, float hinge pin binding or installed improperly, float needle positive opening spring clip binding and causing float to bind and not close the float needle. To be honest Mud’s second choice probably is the real problem over 80 percent of the time. Dirt/crud not letting it seat properly, one of my pet peeves is those who use Teflon tape on fuel line connections, remnants of that stuff really love to find there way into the space between the float needle and its seat.

A new carburetor kit was installed a couple of years ago. It was running fine a few weeks ago. Should I bend the floats down in order to put more pressure on the pin?

 

[used red MN]

A new carburetor kit was installed a couple of years ago. It was running fine a few weeks ago. Should I bend the floats down in order to put more pressure on the pin?

The “bending” of the float as you say adjusts the fuel level in the bowl it does not really “put more pressure” on anything. Make sure the float needle point looks good (this might require a magnifying glass) and make sure there is no dirt or debris in the needle seat or above it!

 

[kensikora1]

The “bending” of the float as you say adjusts the fuel level in the bowl it does not really “put more pressure” on anything. Make sure the float needle point looks good (this might require a magnifying glass) and make sure there is no dirt or debris in the needle seat or above it!

Thank you!! I’ll take it apart and check again.
Green Bay