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TomF

advice on Big Ten carb

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TomF
We've taken a Flo-Jet carburetor from one of our 1965 A-C Big Tens apart for a good cleaning. In the process, we replaced the main jet needle and the brass emulsion tube. We cleaned everything and put it back together. Now it continually drips gas. We're thinking we may need to replace the viton-tipped inlet valve that is controlled by the float. Could this non-stop flow of gas be caused by something else? The tip on this valve looked fine as far as we could tell. Thanks for your guidance.......... Tom

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BradW
Is the drip caused by leaking or overflowing? If overflowing the viton-tipped valve isn't shutting off the flow of fuel. It could be a worn valve, or a speck of dirt in the valve. Or, the float may not be raising as the fuel level raises because it is leaking, saturated, hanging up, or may not be properly intalled or adjusted. Was the carb dripping before it was disassembled?

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TomF
The carb was not leaking before disassembly. If overflowing, where would I look for gas to be leaking from? I didn't notice very well where it was dripping from. We were outside on the driveway at night with a spotlight on. My suspicion is that the float is not closing the valve, but I'm not sure what to look for or how to diagnose it. Thanks, Herb - any further counsel is appreciated! Tom

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TomF
We took the carb off the tractor last night. We raised the carb above the gas tank, then hooked up the fuel line. We then looked straight down into the open throat of the carb. I lowered the carb assy. to allow the bowl to fill. After a short time, it appeared gas began running into the bottom "Welsh plug tube" from the front of the tractor. This would be from the direction of the main jet. We had the main jet needle open 1.5 turns. Any ideas on what we need to correct? Could this be the inlet-needle above the float not sealing shut when the bowl is full? A local fellow suggested the inlet needle needed a brass seat, but I only saw a conical hole in the cast carb body - no brass seat. Hmmmmmmmmm........ Or is it the main jet as Bill suggested? If it is the main jet, what do we need to change? I am at a loss what to think, not being as wise as youall....;) Thanks! Help! Tom

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Al
Al, ARE THESE YOUR POSTS WE WERE THINKING ABOUT? ************************************ "The problem may be the nozzle above the main jet. there is a flange that looks like the face on an engine valve. This seals to the carb casting. If it leaks the gas runs from the float bowl into the intake of the carb. The float valve will keep letting it in as long as this lets it run out. There is a possible fix if this is the problem. Take an old nozzle and sand [NO BRASS OR ALUMINUM ON A GRINDING WHEEL, PLUGS THEM UP AND RUINS THEM] the threads off the nozzle then using some fine valve lapping compound or agressive tooth paste, lap the seat using this modified nozzle. Next get a new nozzle and I will get a part number for a kit that has some small teflon washers that will slip over the nozzle and hopefully seal it. IF this is what is leaking, you have nothing to lose as you will need a new carb casting to fix it otherwise. Just be sure this is the problem first. If your float valve pressure tests OK This is a likely suspect. Good luck, Al" FOLLOW UP " Hi, The other night I talked about leaking carb nozzles and a possible fix. Said I would post a part # for washers. Meant to do it last night, but worked on drawings and procedures for 700/7000 /18 Vangard kits till 2:10 am and forgot. Here it is: This is a tank repair kit for a 5 hp with the top of the tank warped so the gasket won't seal and it won't pump fuel. It contains several maybe 6 or more washers that can be used to do the "nozzle fix" The kit is around 2 or 3 bucks. Briggs part # 391413. Sorry I'm late, Good luck, Al"

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TomF
If the carb was not leaking before disassembly AND all the disassebled parts were reinstalled, I wouldn't think you would now need some kind of additional brass seat. Of course, it is always possible some part got lost when the carb was disassembled. What does your parts book show? If the viton tipped inlet valve is working, then you should pursue Bill's comments regarding the main jet not seating. I think there was a detailed discussion about this a while ago. Did you do a "search?" Just one other point. Sometimes a carb valve, needle, jet, or seat may "look" good to the eye when there is a problem.

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Ishmael2k
Tom, I'd get the teflon washer and try it. Won't hurt anything and they run about $.20 (At least my dealer sells them by the piece since it is a fairly well known fix for those cranky updraft carbs.. Darn B&S anyway...). Rob

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TomF
It sounds like I should do a "pressure test" on the float valve first before attempting the teflon washer trick. How does one do that, and are any Briggs tools required? Thanks one more time..........Tom and glum son Peter

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