H carb gas leak

Zachary Hoyt · Feb 18, 2011

I have been running a carb for the past 7 months or so that was
missing the cap over the metering device, I think. Anyhow it
was missing the conical cap with the screwdriver slot on the
front of the carb. I bought a used carb in November but didn't
put it on the tractor till now. The tractor runs well with the new
carb but whether I shut the mag off or close the fuel shutoff and
let the tractor die it begins to drip gas from somewhere on the
bowl of the carb. I tried to take some pictures to show what it is
doing. It seems to be running uphill from wherever it is coming
out, or something. I am at a loss as to what to do next. Any
advice will be very much appreciated.
Zach

Owen Aaland · Feb 18, 2011

The brass nut with the screw driver slot hold the metering nozzle in place in the fuel bowl. It appears that the gasket is leaking between that nut and the fuel bowl and the fuel running down and back from there.

You are also missing the felt filter and retainer from the drip hole. Without it dirt can enter the carburetor without going through the air filter.

glennster · Feb 18, 2011

also check real close around the square head plug. my h has a hair line crack where the plug was over tightened at some point in the past, and somebody tried to braze it.

Zachary Hoyt · Feb 18, 2011

Thanks, I'll try that out. Would the gasket and the felt and retainer
be in a carb kit, or are they things I can get in some other way?
Does the screw slot cap unscrew in the normal direction? Thank
you very much.
Zach

Zachary Hoyt · Feb 18, 2011

Thank you very much, I will look for that. It seems like a good possibility too. Maybe a bright light will help.
Zach

Janicholson · Feb 18, 2011

There are no left handed threads in it. Leakage can also be from a sticky float, or a leaky needle/seat in the inlet. The fuel just fills up the bowl and leaks out over the top of the bottom part of the carb. Jim

Zachary Hoyt · Feb 18, 2011

Thank you very much for your advice. I had thought it couldn't be the needle and seat or the float because it leaked in just the same way when I had shut off the gas at the sediment bowl and let the tractor run till it stalled, but could it be that there is still enough gas to be coming in and overflowing it but not enough for it to run on? I don't know much of anything about how they work internally.
Thanks again.
Zach

Janicholson · Feb 18, 2011

Any felt from a craft store about 3/32 thick (doubled common felt) will do. a spring (star) washer that is ground down on its outside edge to be a tiny bit larger than the hole will hold it in the carb overflow.
THe square plug (as mentioned) does look like a potential leak. Careful use of teflon tape (keeping it out of the carb and on the threads) can seal it unless the bowl is cracked. The needle in the brass fitting is also equipped with a packing that can become old and hard, allowing a leak around the needle. Be sure to maintain the adjustment of the screw if you take it out, (count the turns and be careful) Jim

Zachary Hoyt · Feb 19, 2011

Thank you very much for the tips. That sounds like I should be able to do those things.
Zach

H carb gas leak

Zachary Hoyt

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Owen Aaland

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glennster

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Zachary Hoyt

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Zachary Hoyt

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Janicholson

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Zachary Hoyt

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Janicholson

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Zachary Hoyt

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