Outdoor Power Equipment and Small Engines - Tecumseh starts, won't run. 2 cycle carb (?)

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ponchov8
04-30-07, 08:25 PM
I'm trying to clean the main fuel inlet into the carb.
I have a Sears 3.5 hp 2 cycle auger that can start by priming the carb with gas, but will not run. I've tried several things and now have the carb off to clean it out. I don't think the main fuel feed is working because if I blow carb cleaner into the carb inlet, nothing comes out of the jet in the venturi (if that's where it's supposed to go). If I blow cleaner in and operate the needle under the primer diaphram, fuel will come thru that circuit--for starting. Removing the idle and hi speed adjuster screws and spraying cleaner into the hole does deliver fuel to other places in the carb as expected.
So, when gas goes into the carb fule inlet, where is it supposed to go to and come out in the carb? Does it go straight to the main jet in the venturi?
Thanks, Doug


cheese
04-30-07, 08:49 PM
Hello Doug!

The carb cleaner won't come out the venturi when sprayed into the inlet because the needle is closed. This carb won't put fuel into the venturi without the engine running, or at least turning with the choke closed. It relies on pressure pulses from the turning engine to operate the internal pump and metering diaphragm. I'd suggest rebuilding the carb and installing a new kit. Especially if the diaphragm is a bit stiff or distorted.

ponchov8
05-01-07, 03:18 AM
Thanks, that makes me feel more confident that there isn't still an internal blockage. I wonder how to identify the carb for a kit? I've tried googling the stamped numbers on the carb, but get nothing. I guess I can try Sears parts next using the engine model number.
D.