Float valve question

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How long should one reasonably expect a float valve to hold back fuel? Both my lawn tractor and snowblower (2-stroke) have the same problem; if I let them go more than a week or two, the valves seep several ounces of fuel and the engines are flooded. I'd replace the float valve, but they aren't too easy to come by as the tractor is nearly 30 years old and the snowblower is 15 years old. The tractor at least has a shutoff valve to prevent that, but the snowblower doesn't.

Unfortunate since I've cleaned up the carbs with Gumout when they were given to me after sitting for several years, but they run fine if I can get them started. Actually, the tractor starts immediately if I remembered to turn off the fuel last time and turned it on before cranking. The snowblower is especially frustrating since I ran it dry last spring, I gassed it up last week, and it started on the first pull. I tried starting it again last night, and it took over a dozen pulls as it was puking raw gas out of the exhaust until it ran.

Short of trying to find new float valves or replacement carbs, what can I do?
 
The spring tension on the needle & seat is the problem or the needle is not sealing on the seat because of gunk in the seat (Usually Ethanol Residue). You might need to bend the spring slightly (not too much) so that the needle contacts the seat at shut down or clean the seat and needle (or replace). I had this problem with my snowblower.

The float just keeps the bowl full.

If you are having this problem in two pieces of equipment I would be more inclined to think that it's residue on the needle/seat that is causing your problem and it just needs to be cleaned. Taking a Q-Tip soaked in brake cleaning and spinning in the seat and against the needle works well if it fits.

Like this: https://www.youtube.com/watch?v=zlez_hdoWYk (1:41) (I use brake cleaner)
 
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Twp solutions.
Keep fuel tank near empty when storing.
Install a fuel shut off valve in fuel line.
They are cheap.
Amazon has all kinds of deals on them.
 
If you can figure out what the carb is you should be able to find parts pretty easily, 30yrs old isn't that old in terms of small engine parts and the same parts could be and likely are still made. Even discontinued parts show up on Ebay pretty frequently.

Can you tell us what the two machines are?
 
Thanks all. I found a replacement carb for the snowblower on Amazon ($14). After tearing down the old one, I found the amount of gunk inside made it somewhat remarkable the thing actually ran. FYI, it's a Snapper C3203 with a Tecumseh HSK-600 engine. Although it didn't seem to be seeping noticeable amounts of gas, it would flood easily and run rich. Got a new spark plug on the way too, the old one looked pretty cruddy. The tractor is a John Deere RX75 with a Kawasaki FC-290V engine. Some carb parts are still available through the nearby Deere dealer (including a float valve), although the rebuild kit is discontinued.
 
Good
thumbsup2.gif
 
For future referance, the carb on the Tecumseh has an aluminum inlet needle valve and replaceable viton rubber seat. The most common problem with this carb is that the brass float will develop a leak and sink. Simply replacing the needle, seat, and float will solve the problem. This is a simple and cheap repair that can be done on 99% of all Tecumseh 4-cycle engines.
The Kawasaki carb presents a more difficult problem. The float is solid and it is not normally subject to fail. The inlet needle valve has a viton rubber tip and the seat is a machined surface in the aluminum carb body. More often then not, on an engine that old, replacing the needle will not solve the problem, the seat wears/corrodes. The leak cant be fixed, so the carb will typically require replacement. Over the years I have had some occasional successes repairing this carb by lapping the seat using a tool that I made and lapping compound.
 
All my 4 stroke OPE has a shut off. I run them dry after every use. When I forget, the Suzuki/ Hitachi carb will drain the tank on the Toro.
 
Got the new carb and spark plug put on the snowblower, and it started on the second pull. Looking closely at the old carb, I see a few tiny passages that make me wonder if they aren't clogged up in addition to a leaky float. Not bad for a free snowblower that only needed $20 worth of parts. A shutoff valve would be nice, but it would take some doctoring to install since the shrouds surround the engine and gas tank. We'll see how it starts next time after it sits for a little while.
 
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