# Main nozzle check valve



## glenjudy (Aug 26, 2006)

How many of you experienced hands ever replace the main nozzle check valve on Walbro's ??
My friend's Homelite 33cc Bandit came from factory with no fuel filter. WT-707 carb inlet screen totally clogged. Have cleaned and kitted carb and spray comes out main nozzle when carb spray applied thru H passage, but engine doesn't keep running when started.
I'm thinking I might have hurt the check valve when cleaning.
 
thanks,


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## 30yearTech (Sep 14, 2006)

This check valve allows fuel to enter into the venturi of the carburetor and prevents back pressure from the engine from entering the metering chamber of the carburetor. Spraying through the "H" adjustment will allow the spray to come out of the valve, this is normal.

It depends upon which type of check valve you have as to how you would go about replacing it. They are not hard to replace but the procedures vary depending on which type is in your carburetor. When I looked up your carburetor the IPL shows (3) types of valves, if it's the brass colored one these are usually just knocked into the throat of the carburetor with a small punch and hammer. The other types are covered with a welch plug and are easily removed once you take out the welch plug.

The material used in the check valve is pretty durable, I can't recall ever trashing one with spray carburetor cleaner, now if you drop it in a vat of cleaner maybe, but otherwise I would be more inclined to think there may be some debris in it causing it not to work.

Best of Luck.... :thumbsup: :thumbsup:


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## glenjudy (Aug 26, 2006)

30year, as always, thanks!
this carb has the nozzle/check valve protruding into carb throat, with a cup/welch plug. Service manual gives instruction on how to remove.
Thankfully, this unit is designed where the carb is super easy to remove/reinstall.
I just didn't know if the professionals routinely replaced the check valve, or least, not that uncommon.
thanks again,


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