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Checkvalve replacement on Walbro wj-71

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Checkvalve replacement on Walbro wj-71

Old 05-02-2012, 09:17 AM
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zrgq014
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Default Checkvalve replacement on Walbro wj-71

Guys: I need help. I destroyed the high speed jet nozzle checkvalve on my Walbro WJ -71 carb. I have found a source for the nozzle checkvalve but have not found a source for the high speed jet. I believe the jet will be destroyed removing it from the body of the carb. Does anybody know where I can find a source for the jet. Secondarily, does the jet and checkvalve come as a single unit? Thanks Fred
Old 05-02-2012, 10:51 AM
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Default RE: Checkvalve replacement on Walbro wj-71

ORIGINAL: zrgq014

Guys: I need help. I destroyed the high speed jet nozzle checkvalve on my Walbro WJ -71 carb. I have found a source for the nozzle checkvalve but have not found a source for the high speed jet. I believe the jet will be destroyed removing it from the body of the carb. Does anybody know where I can find a source for the jet. Secondarily, does the jet and checkvalve come as a single unit? Thanks Fred
click on view parts list
http://www.ordertree.com/walbro/part...iew/id/235890/
Old 05-02-2012, 11:14 AM
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Default RE: Checkvalve replacement on Walbro wj-71

I'm not sure if the actual HS jet is replaceable. Was the check valve damaged by solvent (carb cleaner?) or mechanical means? Might be time for carb replacement.
Old 05-02-2012, 12:18 PM
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Default RE: Checkvalve replacement on Walbro wj-71

There is no high speed jet listed for that carb on the Walbro site http://wem.walbro.com/walbro/product...71-1&Series=WJ

Most people consider the carb for complete replacement when the HS Nozzle Check Valve is bad
Old 05-02-2012, 01:05 PM
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Default RE: Checkvalve replacement on Walbro wj-71


ORIGINAL: w8ye

There is no high speed jet listed for that carb on the Walbro site http://wem.walbro.com/walbro/product...71-1&Series=WJ

Most people consider the carb for complete replacement when the HS Nozzle Check Valve is bad
That would be my take on this also. The brass nozzle is usually a press fit into the aluminum carb body. There may also be some adhesive on it like they use on the welch plugs.
Old 05-02-2012, 01:52 PM
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Default RE: Checkvalve replacement on Walbro wj-71

Thanks guys; I hate to replace the whole carb for a two dollar part, I was hoping someone had a part replacement solution since the Walbro service manual talks about replacement of the checkvalve. Fred
Old 05-02-2012, 02:22 PM
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Default RE: Checkvalve replacement on Walbro wj-71

You probably can replace the checkvalve after removing the welch plug under the metering diaphram. The biggest problem is installing the new welch plug properly.
Old 05-02-2012, 02:26 PM
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Default RE: Checkvalve replacement on Walbro wj-71

For others reading this, it is generally thought that bad high speed check valves are caused by blowing compressed air down through the check valve at rebuild time. Some people think that certain solvents can contribute to the valve going bad.

It is said that Zama carbs are more prone to easily getting the HS nozzle check valve damaged but I have seen it in Tillotson, Walbro, and Zama carbs.

Typical Indication of a bad HS Nozzle Check Valve

The engine will not maintain a consistent mixture setting at higher speeds even after replacing the metering diaphragm.

Typically you can get the engine all set up correctly, mixture wise, on the ground, and then while in flight, it will go very rich soon after take off and the HS will stay that way.
Old 05-02-2012, 02:51 PM
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Default RE: Checkvalve replacement on Walbro wj-71

i bought mine from DA...this guy sells em too http://www.randysenginerepair.biz/se...-dsh-71/Detail looks a little different than my wj-71

ebay has one also
Old 05-02-2012, 05:17 PM
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Default RE: Checkvalve replacement on Walbro wj-71

The one from Randy's doesn't have the correct arm.
Old 05-02-2012, 07:43 PM
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Default RE: Checkvalve replacement on Walbro wj-71

So, no one here has taken a WJ-71 completely apart or even knows that the high speed nozzle is the high speed jet and is easily replaceable?

Close the choke valve and use a drift to drive the high speed nozzle into the bore of the carburetor, open the choke valve and remove it. Install the new one the same way and the same direction, no Loctite required.

http://www.mowtownusa.com/Walbro-Car...t_p_94276.html
Old 05-02-2012, 07:47 PM
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Default RE: Checkvalve replacement on Walbro wj-71

ORIGINAL: jedijody

So, no one here has taken a WJ-71 completely apart or even knows that the high speed nozzle is the high speed jet and is easily replaceable?

Close the choke valve and use a drift to drive the high speed nozzle into the bore of the carburetor, open the choke valve and remove it. Install the new one the same way and the same direction, no Loctite required.

http://www.mowtownusa.com/Walbro-Car...t_p_94276.html
You are correct Jody ..... was just speaking from general Walbro experience ... not WJ-71 specific. I stated in post #3 that I wasn't sure whether the nozzle was replaceable or not. Thanks for the real scoop.

By the way good to know you are still lurking around here!!
Old 05-02-2012, 10:17 PM
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Default RE: Checkvalve replacement on Walbro wj-71

In my (unfortunate) experience, carb cleaner spray instantly ruins the various check valves in Zama carbs. So far I have not had that problem with Walbro carbs, but just to be certain, I have changed from carb cleaner spray to WD-40 to clean/check the flow on all my carbs. As mentioned, too much high pressure air can also damage them...

AV8TOR
Old 05-03-2012, 05:22 AM
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Default RE: Checkvalve replacement on Walbro wj-71

Wow, our old pal Jody to the rescue. So nice to see you lending your usual helping hand.

Karol
Old 05-03-2012, 06:43 AM
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Default RE: Checkvalve replacement on Walbro wj-71

Double thanks, that will save me a lot of money, Even the local mower shop did not know that the jet and the checkvalve were the same part. I'm a happy camper. Fred
Old 05-03-2012, 11:36 AM
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Default RE: Checkvalve replacement on Walbro wj-71

I didn't think the check valve was all that important, isn't it just to stop some richening when backing off of the throttle.
Old 05-03-2012, 12:14 PM
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Default RE: Checkvalve replacement on Walbro wj-71

That is the official explanation but the engine doesn't run well when one goes bad.

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