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Discussion Starter #1 (Edited)
I've got this Craftsman w Tecumseh engine snowblower. In real good shape except it doesn't keep running.
IT starts great. Runs for a bit then quits. I prime it a bit and/or use the choke again and it starts right up. Runs for maybe 30 seconds to a minute then does the same thing. Yesterday I tried to quickly open the choke when it is dying. This does get it back to run again (no stall). But then it runs and later the same happens.

At first I thought the carb was dirty. Cleaned it (no dirt in bowl), ran it, Still does the same thing. Installed new sparkplug, same thing happens.
Got another cheapie carb off amazon. Does the exact same thing!

I identified the carb, it's the series 3 but not adjustable. The identification page mentions the position of the float bowl. I've had the bowl off of the new carb as well. Could the float bowl being in the wrong position be causing what seems to be the lack of fuel ?
Only other thing I can think of is a new fuel line?

I do have to mention I am at high altitude (7800ft). I found a new main jet online that has the nr 207 on it. The original jet had the nr 184 on it. What do the numbers indicate ? Wouldn't a smaller nr indicate a smaller jet ?
 

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Gas Cap May not be venting, or Needs New Fuel Line.
 

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Like Jack said. Try loosening the gas cap and running it like that, to see if that helps. If the vent is plugged, it won't let air into the tank, and will eventually draw a vacuum, starving the carb for fuel. I'd be surprised to see it happen so quickly, but it's possible.

You also might have a significantly-clogged fuel filter, or a plugged fuel line, either of which is really limiting fuel flow to the bowl. Giving it a trickle when it needs a stream. When the engine dies, this gives the carb some time to refill, from that trickle.

You can pull the fuel line off the carb, then open the fuel shutoff (does it have one?) and observe the flow, draining into a container. It should be a good stream of gas coming from the tank.
 

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Discussion Starter #5
Like Jack said. Try loosening the gas cap and running it like that, to see if that helps. If the vent is plugged, it won't let air into the tank, and will eventually draw a vacuum, starving the carb for fuel. I'd be surprised to see it happen so quickly, but it's possible.

You also might have a significantly-clogged fuel filter, or a plugged fuel line, either of which is really limiting fuel flow to the bowl. Giving it a trickle when it needs a stream. When the engine dies, this gives the carb some time to refill, from that trickle.

You can pull the fuel line off the carb, then open the fuel shutoff (does it have one?) and observe the flow, draining into a container. It should be a good stream of gas coming from the tank.
I will try that, but when I replaced the carb, plenty of fuel came out.

As far as a fuel filter... I don't think I saw a fuel filter anywhere? Are they supposed to have one ? Where is it usually located?
 

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The fuel could be swollen internally and that will cause a restriction. It happens some times, and there is no obvious sign externally on the fuel line. You would have to remove the line and stretch it out straight and look thru it to see if there is any obstruction. It happens, but rare, then just replace the fuel line.
 

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You likely have a small filter inside the gas tank on the outlet for the fuel line. Take a look with a light and see if there isn't one. I've seen them clogged up and crushed so next to no gas got through.

Second is when it's dying, can you hit the primer and see if it continues running? It may not so if that doesn't work have a can of starting fluid handy and give it a quick shot as it's dying and see if it revs up. If it does then it's likely fuel starvation related.
 

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If you messed with carb. , consider possibility of an air leak . I use a plant mister, and water to wet intake manifold at both carb. and block . If engine briefly speeds up, that gasket [ wet ] leaks . Sounds like a clogged high speed jet, idle jets seldom clog .
 

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Fuel filters are typically either inline (somewhere along the length of the fuel line from the tank), or a screen in the tank itself, at the exit to the fuel line. You might be able to look down through the tank's fill hole, and look for a screen. I think mine was easier to see with the tank pretty much empty.
 

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Discussion Starter #10
Thanks all !
Well, I took the carb off again. I noticed the bottom of the carb was wet (w fuel). Upon closer inspection the fuel bowl wasn't seated correctly. I think when it was running it would let some air in or leak fuel , not sure. I took it off and noticed the fuel bowl O ring was too big. Either it stretched out from a bad install or it was too big from the start. I used the old O ring from the original carb and seated the bowl on it. Also made sure the deepest side of the bowl is where the float comes down.
Blower fired right up and now stays running !!

It does seem to run slightly rough. This is probably due to the high altitude I am at. what nr fuel jet is needed ? (see original post)
 
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