Zenith Carb on Onan CCKB

[npalen]

Hi folks--New here, been lurking and now my first post. My recently acquired Allis 720 has some carb problems that someone can hopefully help with. I've had to run with the choke half closed (half open?)to get it to idle half way decent even when warm. Pulled the carb, disassembled and cleaned last evening. Noticed that the two main needles were in bad shape as someone had forced them all the way closed bending the tip on one and breaking it off the other. I know very little about carburetion but have a machinist and shadetree mechanic background. Proceeded to repair the needles as best possible by chucking in the lathe and restoring the ends. When referring to "the two main needles", this Zenith sidedraft has opposed (in line) vertical needle valves. The top one has the needle mounted in the end of a brass tube about 3/32" diameter by a couple inches in length with a tiny hole near each end. The tube was even bent but managed to bring it back reasonable straight. After all the rambling above, I guess my question is how to adjust these two valves with the carb back on the tractor and running. The idle adjustment is a 3rd needle on top of the carb and, of course, the idle speed adjustment screw. Starting to get the bug here so any and all info is greatly appreciated. Anyone know where I might find a carb kit? Thanks Nelson

[Guest]

Onan 19.5 Zenith carburetor: Some service parts for Series 1408, part # 13262 still available but not included in service kit: C54-39-2-27 idle jet tube assembly C63-254 vent tube C66-133 discharge jet C85-129 float C3-132 fuel bowl C29-1593 throttle shaft assembly C21-219 throttle plate C108-294 choke shaft and lever assembly C102-139 choke plate C71-105-34 jet adjustment assembly Overhaul Kit # K2165 Can be purchased at: Bailey Motor Equipment 10501 South Orange Ave Orlando, FL 32824 Phone (407) 422-8134 Phone (800) 394-8134 bmeco@aol.com Mike Fox

[JP]

Hi Nelson, WELCOME Aboard! You might also want to check the output & condition of the fuel pump. If you're using the mechanical one, make sure it's mounted on the fiber spacer. Let us know! JP

[npalen]

[url][/url]http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=78362 Guys--I greatly appreciate all your info and the above thread I found. Gary--Very nice 9020! I can see I have a lot of work to do. Jim--Thanks for the parts list. One thing I see different on my Zenith is that the idle jet tube assembly is adjustable from the top of the carb and includes a needle press fit into the bottom end of the brass tube. Will try to keep you posted (for your entertainment) with my progress and will sure have more questions Many thanks Nelson

[Guest]

See this post for further clarification. http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=76532

[npalen]

Gary--I probably need to replace the idle tube assembly but not sure it's the right one per my post above. Mine has threads for adjustment where the one shown is a press-in. ( C54-39-2-27 idle jet tube assembly) I need to call Bailey and get prices on some of the parts. Thanks again. Nelson

[Guest]

Where are these threads you speak about? Post a picutre if you can.

[npalen]

The second photo shows the idle jet tube assembly installed in the top of the carb. This assembly is in line with the main jet in the underside of the carb.

[Guest]

Your first picture shows a part that comes with the service kit, K2165, and is NOT used with Series 1408, part # 13262 carburetor. If this is 13262 carburetor then someone has installed the wrong part. I'm wondering if there are other screw ups with your carburetor? What you need is C54-39-2-27 idle jet tube assembly or another carburetor.

[npalen]

Put the carb back on the 720 this evening and am now able to run with the choke open. The needle valve on the idle jet tube assembly definitely effects the idle smoothness on the engine. Now need to look into the electrical and see if the points gap needs adjusting, plugs etc.