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Old 12-29-2012, 08:17 AM   #1
mpalilonis
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Default Zenith Carb Rebuild Question

Finishing up rebuilding my carb and noticed that before i started that the Main Jet was a little higher than the Cap Jet, now the shop manual says to make them even. Since I can't lower the Cap Jet anymore, very thin washer with it, I had to add some thicker washers to the Main Jet to get them to the same height. Now they are both at the narrowest part of the Venturi.

My question is, is this correct or is the Main Jet suppose to be slightly higher than the Cap Jet. I bought the carb not to long ago supposedly rebuild, ran great until the other day....long story. Any help would be great.

Mike.
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Old 12-29-2012, 08:36 AM   #2
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Default Re: Zenith Carb Rebuild Question

The jets are supposed to be the same height and normally match with only one gasket beneath. It is possible one or the other jets may be non-stock Model A. There are a lot of similar jets out there made for other applications that end on the the Model A carb. Other possibility...is the cap jet slightly offset to the main or does it sit directly behind it? if directly behind it, you have a double venturi carb.
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Old 12-29-2012, 08:50 AM   #3
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Default Re: Zenith Carb Rebuild Question

Thanks... I did it right then, only have two thin washers on the Main Jet. I bought the rebuild kit from Macs for this carb, all the jets matched the heights of the ones I took out. So I felt comfortable putting it back together. The Cap Jet sits slightly off center, at 10 o'clock. Also, the kit came with two different Compensator Jets... One had a much smaller hole than the other. There is no numbers stamped on it, so which one should I use?
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Old 12-29-2012, 09:15 AM   #4
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Default Re: Zenith Carb Rebuild Question

The smaller comp jet goes in the fuel bowl. The one that looks like a comp jet but is larger is a GAV adjustment needle seat. Remove the GAV adjustment needle housing and shine a light down. The earlier carbs are threaded for the needle seat & you can put a gasket on it & screw it in. The later carbs had an integral seat & don't need this part.
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Old 12-29-2012, 09:27 AM   #5
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Default Re: Zenith Carb Rebuild Question

That's what I have I guess, didn't see anything down the GAV port when I shined a light down it. Thanks for the help!
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Old 12-29-2012, 11:24 AM   #6
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Default Re: Zenith Carb Rebuild Question

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Don't throw out the original jets. Some of us like to use original parts only, as much as possible.
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