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Old 01-18-2013, 08:02 PM   #1
170bdlx
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Default Zenith Carb Rebuild

I am rebuilding three carbs and need some advice about the main and cap jets. I see that both jets should be at the same level in the lower body at the narrowest point in the venturi. All three of mine are not when one washer is added tom each. The main jet is higher on all three carbs. It takes three washers on the main jet to make it level with the cap jet, then they are level and seem to be at the correct point on the venturi. Is this normal?
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Old 01-18-2013, 08:42 PM   #2
Mitch//pa
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Default Re: Zenith Carb Rebuild

Cap jet
When installed with a gasket washer, it's tip should be level with (to 1/16" below) the lower casting shelf that the Venturi sits on.

Main jet
When installed with a washer, its tip should be level with the Lower Casting shelf that the Venturi sits on. So, when you remove a Main Jet, make sure you also dig out the old gasket. If you end up with multiple gaskets installed, it will cause poor performance and leaks, because the Jet tip isn't precisely where it should be in the Venturi.
Ck out this site very informative
http://www.modela.org/components.html
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Old 01-18-2013, 08:47 PM   #3
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Default Re: Zenith Carb Rebuild

The tip of the main jet should be 3/8 inch below the gasket surface of the bowl, and the cap jet should be 7/16 inch below the gasket surface of the bowl.
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Old 01-18-2013, 09:49 PM   #4
Gary WA
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Default Re: Zenith Carb Rebuild

also concave tips, proper diameter and length of the jets!
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Old 01-19-2013, 07:20 PM   #5
170bdlx
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Default Re: Zenith Carb Rebuild

Thanks for the great information. I'm sure this will get the jobe done and am looking forward to trying them on my A.
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Old 01-19-2013, 11:24 PM   #6
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Default Re: Zenith Carb Rebuild

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Quote:
Originally Posted by 170bdlx View Post
I am rebuilding three carbs and need some advice about the main and cap jets. I see that both jets should be at the same level in the lower body at the narrowest point in the venturi. All three of mine are not when one washer is added tom each. The main jet is higher on all three carbs. It takes three washers on the main jet to make it level with the cap jet, then they are level and seem to be at the correct point on the venturi. Is this normal?
Only one washer per jet!! Idle jet NO washer. Make sure there are not other washers in the seats.
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