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Carburetor Problems

3142 Views 6 Replies 4 Participants Last post by  JohnW
I’ve been having chronic carb/fuel problems for over a year now as noted here:
and here:
Most of the time the tractor has been setting up in my shop without being used as a result of these problems. Recently, I am in a bind to get this thing going and have done the following:

1. Thought I had it all figured out till I discovered oil volume was increased (again)
2. Tried to move tractor to shop for work and it wouldn’t start
3. Dumped oil and discovered it was grey with coolant
4. Towed tractor to shop and replaced head gasket (and any other gasket I could)
5. Added new O-ring to the valve at the bottom of the tank (it appears to be holding)
6. Added manual fuel shut-off valve near carb to prevent losing all my gas again
7. Replaced battery, coil resistor and coil and got it running again (albeit somewhat rough)

As of right now, fuel flows out of the carburetor if I leave the valve open when the tractor is not running. It does run (poorly) and I can move it around and “use” it, but there is obviously a major carburetor problem. Before I reinstalled the carburetor, I had blown into the fuel inlet line while the carb was upside down to see if the float would seal up the needle/seat and it felt like it was making a good seal, so I don’t understand why it is not now sealing now that it has gas in it. I don’t think it is a problem with the float becoming filled with gas because the fuel was flowing out of the carburetor within seconds of filling the carb up for the first time. It simply is not shutting off the flow of fuel. I guess my next step is to rebuild the carb again, but my lack of success on the first rebuild has me feeling unworthy to the task. Is there something I may have done wrong that you can think of?
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Sounds to me like your float valve and needle are not seating properly..Just a guess..
I beleive you are 100% correct.
Bad needle and seat or possibly the gasket under the seat is missing or it is not tight.
possibly the gasket under the seat is missing or it is not tight.
Since the needle/seat is brand new, I don't think it is that. But the gasket part...well, that is interesting. I guess I will have to pull it apart to take a look at that.
I bought a Standard Hy-Grade carb kit once with a deformed seat right out of the box; never bought another, only Borg Warner. Have you considered that your carb might not be into 'rock'? There might be a fine crack in the fuel inlet passage. I'd deal with it off the tractor using regulated low pressure air. Pay attention to corrosion at the float pivot pin &/or the float pivot area. I'd examine the float with extreme prejudice for leakage as well. When carb rebuilding was my primary side-line I used to sub Viton tipped needles for the solid metal ones which were troublesome. Occasionally, 'lapping' the needle & seat with toothpaste & a piece of vacuum line for a handle would put things right. Perhaps a light spring under the float, or a torsion spring at the float pivot pin would be enough to restore proper function. Be extra careful with Teflon tape; the least remnant of it can cause flooding or a restriction in a metering passage. There is Teflon paste available which is a little safer & works great for lubing/sealing head bolts in water jackets. A note on the gasket suggestion; a very few carbs used a selectable thickness gasket under the seat to set the float level (float 'tang' was NOT adjustable).
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It seems like more and more the parts in the kits are bad.
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