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Old 01-14-2014, 11:02 AM   #1
Chip A
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Question Zineth air balanced carb compensator jet

Good morning folks,

I'm in the process of overhauling my three year old Zenith Air Balanced carb. (Purchased from MAC's three years ago).. In the disassemble process, I was very careful to place everything on a felt mat so they would go back exactly where they came from. Nice plan, but the plastic basin the mat was in got hit and knocked on the floor...... For anyone who has overhauled the air balanced Zenith, there are two jets that are physically the same size...I believe they are both 10-32 X apx 1/4 inch.

My question is this: Which jet is the compensator jet that is installed in the bottom of the float bowl?? The smaller orifice or the one with the larger orifice????? Thanks
Chip A
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Old 01-14-2014, 01:32 PM   #2
H. L. Chauvin
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Default Re: Zineth air balanced carb compensator jet

Hi Chip,

Hate to see 0 responses; but honestly I have no direct technical answer.

In trying to assist if nobody responds, just try it one way, then the other way.

Then go with the way it works best.

Over 99% of suggested solutions I learned in life that worked, came from my fearless father & others who never finished school.
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Old 01-14-2014, 01:32 PM   #3
Gary WA
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Default Re: Zineth air balanced carb compensator jet

here you go. left picture one with #19 is comp jet the other is needle seat-#38 on it. they are 5mm 75pitch tap french made as per Henry.
Attached Images
File Type: jpg comp jet.jpg (33.5 KB, 110 views)
File Type: jpg 02.jpg (76.3 KB, 28 views)
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Last edited by Gary WA; 01-14-2014 at 04:29 PM.
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Old 01-14-2014, 02:13 PM   #4
Chip A
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Smile Re: Zineth air balanced carb compensator jet

Thanks Guys,

So, if I read the attachment correctly, the comp jet is the larger of the two orifice wise....i.e. greater flow and it is also the longer of the two...
After I had posted the questions, I found (By accident) a page that showed some info that goes along with what you guys posted. It looks like the comp jet is a #63 .037 with a 138-142 cc/min flow rate. The Idle jet (Air balanced Zenith 2) should be a #75 .021 with a 38-42 cc/min flow rate.

If anyone comes up with anything else, please let me know. I going to hold off on reassemble until tomorrow. It's January in Connecticut, so there's NO rush.....LOL Thanks again
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Old 01-14-2014, 02:21 PM   #5
Gary WA
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Default Re: Zineth air balanced carb compensator jet

Quote:
Originally Posted by Chip A View Post
Thanks Guys,

So, if I read the attachment correctly, the comp jet is the larger of the two orifice wise....i.e. greater flow and it is also the longer of the two...
After I had posted the questions, I found (By accident) a page that showed some info that goes along with what you guys posted. It looks like the comp jet is a #63 .037 with a 138-142 cc/min flow rate. The Idle jet (Air balanced Zenith 2) should be a #75 .021 with a 38-42 cc/min flow rate.

If anyone comes up with anything else, please let me know. I going to hold off on reassemble until tomorrow. It's January in Connecticut, so there's NO rush.....LOL Thanks again
other way around! short is comp jet with the #19 on the top.
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Old 01-14-2014, 02:30 PM   #6
Chip A
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Default Re: Zineth air balanced carb compensator jet

Thanks Gary..Good catch !
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Old 01-14-2014, 02:54 PM   #7
dave in australia
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Default Re: Zineth air balanced carb compensator jet

Quote:
Originally Posted by Gary WA View Post
here you go. left picture one with #19 is comp jet the other is needle seat-#38 on it. they are 17mm 75pitch tap french made as per Henry.
I don't think they're 17 mm. That's nearly 3/4" and a 75 pitch is one thread per 3". Maybe .75 pitch which would be close to 32 TPI. Also if you meant 1.7 mm, then that would be close to 1/16". 1/4" is close to 6mm. So maybe they're a 6mm x .75 pitch in metric.
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Old 01-14-2014, 03:21 PM   #8
Purdy Swoft
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Default Re: Zineth air balanced carb compensator jet

The other Zenith part that resembles the compensator jet is the adjusting needle seat and was used until jan.1930 , after that it waspart of the casting and not removable. The hole in the adjusting needle seat has a tapered seat in the screw driver slot. The compensator jet doesn't have the tapered seat in the hole. The parts look very similiar. The needle seat goes under the needle of the GAV. If the parts get mixed up, it will still run but not exactly right.
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Old 01-14-2014, 03:58 PM   #9
Benson
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Default Re: Zineth air balanced carb compensator jet

About limited responses to this post ... the text says new carb and air balanced carb so I for one assumed it was about the new Zenith Forklift carb about which I know nothing.

5mm .75 is the jet thread size.

Last edited by Benson; 01-14-2014 at 04:04 PM.
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Old 01-14-2014, 04:30 PM   #10
Gary WA
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Default Re: Zineth air balanced carb compensator jet

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Originally Posted by dave in australia View Post
I don't think they're 17 mm. That's nearly 3/4" and a 75 pitch is one thread per 3". Maybe .75 pitch which would be close to 32 TPI. Also if you meant 1.7 mm, then that would be close to 1/16". 1/4" is close to 6mm. So maybe they're a 6mm x .75 pitch in metric.
my mistake not thinking 5mm 75 pitch
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Old 01-14-2014, 08:11 PM   #11
Chip A
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Default Re: Zineth air balanced carb compensator jet

Sorry if I caused heartburn guys.... It is a "New" Zenith "air balanced" carb.. Sold by MAC's and Sniders for $450.00.. Due to problems that were not their fault, it needed to be overhauled and try as I did to keep the parts in the exact order they came out, the tray was knocked over. Thanks to all for the input.

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Old 01-14-2014, 09:02 PM   #12
Gary WA
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Default Re: Zineth air balanced carb compensator jet

Quote:
Originally Posted by Chip A View Post
Sorry if I caused heartburn guys.... It is a "New" Zenith "air balanced" carb.. Sold by MAC's and Sniders for $450.00.. Due to problems that were not their fault, it needed to be overhauled and try as I did to keep the parts in the exact order they came out, the tray was knocked over. Thanks to all for the input.

Chip
Thanks for clarifying. my mistake to.
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Old 01-15-2014, 08:27 AM   #13
Chip A
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Default Re: Zineth air balanced carb compensator jet

Well, they say confession is good for the soul...LOL so, here is my confession for the day. What I was looking at as the "Idle Jet" was actually the older style Zenith mixture seat.. The "New" style has that already machined into the body. The idle jet is a long tube style. When I went to match up old parts to new parts, there was no OLDER other short style jet. Only the Comp jet... Engage brain long before asking for help....LOL.LOL.LOL Thanks again guys.
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Old 01-15-2014, 12:03 PM   #14
Purdy Swoft
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Default Re: Zineth air balanced carb compensator jet

I think that I explained it in post number eight, yesterday.
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Old 01-15-2014, 02:48 PM   #15
Chip A
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Default Re: Zineth air balanced carb compensator jet

Purdy....you did a yoman's job of explaining it too... It was me.. I was looking at the wrong jet and thinking it was the idle jet....My bad..not yours.
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