Craftsman Weedeater Zama C1U W32-A Carb

homegrown55(9)June 19, 2010

This carb has the external purge bulb. Of issue to me is the idle circuit check-valve. At what points during engine operation is the valve supposed to be "open" and at what point is it "closed."? I have read the Zama Tech Guide PDF file. I have seen the detailed parts breakdown diagram for this carb. I have tested the Hi-Speed circuit with fuel line tubing and can feel and hear the check valve closing in the Main Nozzle. Same test reveals a constantly open idle circuit. Does a welch plug cover the check-valve to the idle circuit in the metering chamber? Is the valve located just under the plug or closer to the 3 ports in the carb throat? I experience minor flooding after using the purge bulb with a no-start condition. If it is maybe a leaking welch plug, is fuel from the metering chamber leaking down into the idle circuit while the engine is not running during the startup procedure? It shouldn't be an issue when it is running as all 3 idle ports in the carb throat are supposed to be contributing fuel during WOT. In other words...can a bad idle circuit check- valve cause a 32cc engine not to start? Any way to fix it?

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I've never worried about the idle check valve, removing the L needle and squirting carb spray thru the L needle inlet, you should see spray exit all the idle progression passages in the carb throat, if this happens, you're good to go.

    Bookmark   June 19, 2010 at 5:59PM
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I understand that but I am finding that once the check-valves in a Zama (idle circuit or primer base assembly and esp. main nozzle)go bad, the unit is severely prone to flooding and no-starts seem to be the rule. This renders the darn thing useless. Must be a marketing ploy on Zama's part. On the Zama site, they have a NEW product that they say eliminates flooding! So, how about a GIANT recall of all the inferior carbs they have produced with less than stellar parts in exchange for the model that would fit your hand-held machine and NEVER flood? I think Walbro is/was a better product.

    Bookmark   June 22, 2010 at 6:11PM
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Don't know about Zama , but Walbro has been a major Supplier of Chainsaw Carbs for Yrs . They were also a Supplier of numerous Snowmobile Engine Manufacturers in the late 60's and early 70 's . Quality Performance Carburation was their Niche . I believe Efco and Solo also utilize Walbro on a select number of their current Saws. It would be interesting to know if any current Grass Trimmer manufacturers use Walbro currently .

    Bookmark   June 23, 2010 at 12:37PM
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