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Subject: Zenith Carbs

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Larry Holbrook    Posted 04-04-2019 at 04:46:22 [URL] [DELETE]        [Reply] [Email]  
  • Zenith Carbs
  • My 3000 has a Zenith Carb on it. Anyone know anything about them? I've looked all over the net and can't really find anything on them. Tractor runs pretty good at higher RPMs. At idle it seems to be running rich. I do not really see anywhere on it to adjust anything. They come with Holly Carbs on them and someone must have changed it to Zenith.

    K.LaRue-VA    Posted 04-04-2019 at 14:56:07 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Zenith Carbs
  • One of my tractors came with a Zenith. I have a collection of original MS, the Zenith, and several aftermarket MS replacements. The Zenith casting and finish quality compares well to the original MS carbs (maybe better). The aftermarket replacements for MS carbs may look similar, but they are all junk based on casting and finish quality. Many of the holes in the replacement carbs are not properly centered in the casting. When the build quality isn't so bad that they are not rebuildable all of these carbs will run well. I honestly couldn't tell you which carb happens to be on my tractors today without looking at them. They all run and function exactly the same if they are clean and adjusted properly. I have several carbs that I rotate so I can keep a couple clean ones ready to swap if there is a problem. Earlier issues with ethanol fuel caused my carbs to foul up in as little as 6 months. That problem has cleared up to the point I haven't had to swap for a clean carb in more than two years.

    Larry Holbrook    Posted 04-04-2019 at 15:40:07 [URL] [DELETE]        [Reply] [Email]  
  • Re: Zenith Carbs
  • The idle screw adjustment worked great. It was out to far around 2 turns. I got it going smooth at around 1 turn out. Idles very smooth now. Tachometer says around 600 RPM. Thanks for the info.

    Larry Holbrook    Posted 04-04-2019 at 15:37:49 [URL] [DELETE]        [Reply] [Email]  
  • Re: Zenith Carbs
  • I agree with you on the non ethanol fuel. I've ran all my chain saws and other 2 cycle engines on it for years. Only station here that sells it has premium only. It's kind of salty. I don't use much in the tractor really so next time I'll fill with it. I adjusted the idle and it is idling smooth now.

    K.LaRue-VA    Posted 04-05-2019 at 07:45:36 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Zenith Carbs
  • Looks like my reply was misleading. I've always run regular pump gas in everything. By the time ethanol problems appeared all my tools and tractors were already completely messed up. It was too late to look for gas that didn't have ethanol in it. All my tanks and cans were full of it and I didn't want to pay premium prices for non-ethanol gas either. The problem with my small engine tools was rubber tubing and other fuel system parts that turned to mush with ethanol in the fuel. Replacement fuel kits came with parts that didn't turn to mush. Problem solved. Troubles with my tractor carbs lasted about a year or so. I "solved" the carb problem by keeping a couple of clean carbs always ready to go. The dirty ones didn't need a kit, they just needed a colorful goo cleaned out of the fuel bowl and passages. Rather than buying rebuild kits, I just bought carb gaskets. At that time it was looking like swapping for a clean carb every six months was going to be the new normal for my tractors. Then I realized it had been more than a year since I had to swap a carb. Apparently it took the fuel companies a while to came up with additives to correct the problems. It has now been several years since I had any problems that could be blamed on ethanol.

    Ultradog MN    Posted 04-04-2019 at 07:20:50 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Zenith Carbs
  • There is a idle adjustment on the front end of the carb.
    See yellow pencil.
    I would try adjusting that a bit.
    The Zeniths are good, reliable carburators. Kits are readily available for them.
    Generally though, like a good ol MS carb they just need a good cleaning.
    Bad gas, you know? I open them up and use a torch tip cleaner to clean all the jets, etc then blow them out good. If you are careful on disassembly you can reuse the gaskets.
    The Holleys that were originally on the 3 cyl tractors were actually a better carb. They used a vacuum controlled "Economizer valve" (think accelerator valve) which made them very efficient. Trouble is the bore that the EC slides in were made of pot metal and after 50 years are worn and not replaceable. They are rather complicated and cold blooded too. If you are a Good carb man you can sometimes get them to work ok. I'm not so I usually pretend I'm Tom Brady and give them my very best heave into the nearest swamp, dumpster or scrap pile.
    Be glad you have a Zenith. A new one costs about $450! They use more fuel but will make your tractor RUN.
    If the photo doesn't show click the link.

    Larry    Posted 04-04-2019 at 13:50:18 [URL] [DELETE]        [Reply] [Email]  
  • Re: Zenith Carbs
  • Thanks I see that adjustment screw now. When I got the tractor it was overhauled and painted like new. Painted the carb blue also. I thought that was a bolt since it had all the paint on it. The spring part was covered in paint. I'll try the adjustment now. If needs be I'll take it off and clean it up like you advised. It seems to run fine when working at 1/2 or 3/4 throttle. Not much info out there that I could locate on the net. Thanks again.

    Tim Daley(MI)    Posted 04-04-2019 at 06:36:33 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Zenith Carbs
  • FORD has been using ZENTIH carbs as far back as the Model T & A. Carb kits sold today are made for all and Zenith parts are almost the same as the M/S carbs. There are several aftermarket clones today, most are junk, so just because it isn't an OEM Marvel-Schebler carb doesn't mean it is a ZENITH. Frequent Flyer member here Ultradog may chime in as he is the resident Thousand Series guy and probably can help you with the Zenith parts.

    Tim Daley(MI)

    Larry Holbrook    Posted 04-04-2019 at 13:51:55 [URL] [DELETE]        [Reply] [Email]  
  • Re: Zenith Carbs
  • Thanks he did. It is definitely a Zenith.

    steve19438    Posted 04-04-2019 at 06:07:23 [URL] [DELETE]        [Reply] [Email]  
  • Re: Zenith Carbs
  • I have two Fergs with Z carbs. junk if you ask me and parts are almost non existent.

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