Needle valve problems, Zeith-2

[Werner]

Hello at all,


I would like to hear about the experiences of the wider community regarding the Zenith-2 carburetor.


Again and again the float needle valve gets stuck in the "open" position while driving; the engine floods with fuel, and it drips heavily from the carburetor.
I have now installed the third float needle valve from DonSnyder, but yet the problem keeps occurring.
The float remains airtight when I submerge it in hot water.


Has anyone else experienced this? Thank you at all fore helpin' hints!

 

[Mike1291]

I've had the same problem and I originally thought it was the needle & seat. I tested the seat and it closes properly, and holds pressure, when the float rises. But gas would still leak. Even a new one would leak. My guess is that the upper body of the carb has a crack somewhere in it where it can leak fuel past the needle & seat which was causing my problems, so I gave up on my carb and got a new one.

 

[jb-ob]

Werner,

After mileage and 'heat soak', retighten the needle valve and all the jets.

I gave up using poorly machined repos, the rubber tipped ones that dissolve in fuel and now hunt for the original Zenith designed ones = no drips.

Best,

 

[Gary WA]

I've had the same problem and I originally thought it was the needle & seat. I tested the seat and it closes properly, and holds pressure, when the float rises. But gas would still leak. Even a new one would leak. My guess is that the upper body of the carb has a crack somewhere in it where it can leak fuel past the needle & seat which was causing my problems, so I gave up on my carb and got a new one.

Jet length is also important and properly dished.!

 

[Werner]

jb-ob,
you're right. I recently bought two weeks ago a Snyder's float needle valve. It started leaking after just one night. The cause was the rubber O-ring seal swelling up; the supposed "Viton needle" turned out to be bare steel.


Unfortunately, I don't know of a source for reliable valves. Quality is more important to me than a low price.

 

[Jim/GA]

Hello at all,


I would like to hear about the experiences of the wider community regarding the Zenith-2 carburetor.


Again and again the float needle valve gets stuck in the "open" position while driving; the engine floods with fuel, and it drips heavily from the carburetor.
I have now installed the third float needle valve from DonSnyder, but yet the problem keeps occurring.
The float remains airtight when I submerge it in hot water.


Has anyone else experienced this? Thank you at all fore helpin' hints!

If the float drops a lot and the needle jams a bit in the housing, it does not want to go back up and seal. The float does not need to go too far for the fuel to flow well.

There is a small tab on the float that is bent to prevent the float from dropping too far. If bent incorrectly, it will also jam the float down and open, preventing it from closing. So look at your tab. Set it to stop the float from dropping too far. Then make sure it does not jam.

 

[Ruth]

jb-ob,
you're right. I recently bought two weeks ago a Snyder's float needle valve. It started leaking after just one night. The cause was the rubber O-ring seal swelling up; the supposed "Viton needle" turned out to be bare steel.


Unfortunately, I don't know of a source for reliable valves. Quality is more important to me than a low price.

Try Bert's. They have "original style" valves and Modern style with "o" ring.
https://modelastore.com/products/a-...e-original-style?_pos=30&_sid=bd16aa802&_ss=r

 

[mercman from oz]

Gary WA

 

[nkaminar]

Using rubber seals in a carburetor that dissolve in gasoline is like having a fish that dissolves in water.

 

[Werner]

If the float drops a lot and the needle jams a bit in the housing, it does not want to go back up and seal. The float does not need to go too far for the fuel to flow well.

There is a small tab on the float that is bent to prevent the float from dropping too far. If bent incorrectly, it will also jam the float down and open, preventing it from closing. So look at your tab. Set it to stop the float from dropping too far. Then make sure it does not jam.

Very, very good advice—and double thanks to Jim. The red float nose was rubbing against the side of the green axle guide.