Snowblower Carb rebuild gone bad?

I've got an old Toro CCR [3horse?] that was showing signs of carb problems last year so I rebuilt it last week.
The carb is a diaphragm type on a Tecumseh HSK600-1680s.[replacement carb is 640086A - the only numbers on this one are '744 9BS']
I knocked out the 2 welch plugs and soaked the carb overnight in carb cleaner.
Cleaned the plastic needle- it looked fine.
Cleaned gas tank [plastic] and replaced gasoline.
After the rebuild I started it up and it ran ok at factory- warmed it up, adjusted to what sounded real good. . . and waited for snow.
That was only a week ago, but today I couldn't keep it running. Primed it, and it started fine- but it acted like it wasn't pumping gas. As soon as the primed gas ran out, it died. Tried adjusting the carb back to factory- but it wouldn't stay running for more than about 30 seconds. I repeated it often enough to warm the thing up, but it still won't stay running.
I'll play with it more tomorrow- but I'm wondering if someone has run across this before.
Because it doesn't seem to be pumping, my first thought is that I put the diaphragm in wrong, but then why did it run so well last week?
Thanks, Jim
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Someetimes the float needle sticks in the seat. Tip the machine on its side, take the float bowl off, wiggle the float. Make sure the needle moves.
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Christopher A. Young;
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"Jim Elbrecht" < snipped-for-privacy@email.com> wrote in message
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On Mon, 3 Dec 2007 19:28:56 -0500, "Stormin Mormon"

diaphragm carb- so no float. But I took the thing apart again- the needle seemed to be moving freely, and sent bubbles back up the gas line when I worked it. [clear line has an advantage] But still no joy on running without constant priming.
The carbs are <$50. Probably should have gone with a new one in the first place.
Jim
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I have a old snowblower with Brigs and Stratton 5.5 eng. The unit has no primer bulb or button .Problem is in order to start this guy I need to pore a shot glass of gas in the spark plug hole. Would a carb kit help? Eng is Brigs #110900 Frank
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wrote:

Might help - the carb kits are cheap enough. Or you could end up like me and spend $12 on a kit- $10 more on cleaner. . . a couple hours working . . . and then buying a new carb.<g>
For yours the carb is about $65 here- http://www.psep2.biz/pages/parts/viewbybrand/10/BriggsStratton.aspx
Jim
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They also make an aftermarket gas cap for Briggs that has a primer built-in.
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I've seen this kind of problem before. Very likelly, you have a bad gasket between the carb and the engine body. So, it's sucking in pure air, instead of gas mix. Just pull the carb off (two bolts) and put a little Permatex #2 non hardening gasket sealer on both sides of the gasket. Reassemble, and see if that helps.
Other option, you may have a choke that's not shutting.
Pore is a small hole. Pour is to dispense liquid.
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"Frank" < snipped-for-privacy@comcast.net> wrote in message
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wrote:

Check your oil-fuel mix ratio. I had similar problems with mine for three seasons. Did the strip down clean up routine too. Having done everything mechanically reasonable the only thing left was the 50:1 fuel-oil mix ratio as embossed on the fuel cap. That fixed the problem. I had been doing the mix by guesswork and inevitably there was "ratio creep." Get a calibrated plastic squeeze bottle from the Dollar Store to store your 2-stroke oil. 40 ml mixed in a 2 liter pop bottle is just the right amount for (my) a single snow clearing chore.
Among the many fixes I tried I had heated the cylinder head with a paint stripper heat gun to get the snowblower going from a lower than minus 20 C cold start. I don't have to do that any more but I find a half minute's heating the carb cup really helps to get the machine started with a pull or two in the coldest weather.
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[snip]
How is the fuel flow to the carb? Fuel line clear? Tank vent open?
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