The Ford Barn

EdB · 11-25-2017, 04:34 PM

is the inside diameter on the cap, main & idle jets all supposed the same?
The 'A' sat for a long time; I inserted a paper clip thru them to clean & have been experience backfire after running temperature is reached.
Thanks.

Ron in Quincy · 11-25-2017, 05:04 PM

If you could run a Paperclip through the jets then the opening is way to large on all the jets. As a example, a original idle jet will have a #11 and is usually .021 orface, the comp. jet is usually a #19 .037 orface. All original jets are numbered; replacement jets are not numbered, and some of them are junk.

Your Zenith-2 indicates it was built by Holley Co., providing it has a Holley Top. The Zenith-1 was built by Zenith Co. They both use the same jets.

Ron

Terry, NJ · 11-25-2017, 06:04 PM

REVISION! I was not happy with the readings I got last night in the cold, and with a vernier. Tonight I went back in to do the job right. After screwing around with a couple of carburetors until I got one I could get the butterfly screws out of and remove the throttle shaft. I miked it with a micrometer, not a vernier. Shaft Dia. was .279, that's more like it! I then stuck a 9/32 (.281) drill blank into the bore and shook it around. It was a good fit and I estimated about .001-2 slop so the bore size is .2815-.282 with a shaft dia. of .279 is about .0025 to.003 clearance. I, myself wouldn't bother with oversize shafts or bushings to gain what? Sorry for the confusion last night.
Terry

Tom Endy · 11-25-2017, 07:23 PM

Sponsored Links (Register now to hide all advertisements)

See attached document. Pages 12 and 13 addresses jet sizes.

Tom Endy

11-25-2017, 05:04 PM	#2
Ron in Quincy Senior Member Join Date: May 2010 Location: Quincy, CA. Posts: 1,708	Re: Zenith 2 carb If you could run a Paperclip through the jets then the opening is way to large on all the jets. As a example, a original idle jet will have a #11 and is usually .021 orface, the comp. jet is usually a #19 .037 orface. All original jets are numbered; replacement jets are not numbered, and some of them are junk. Your Zenith-2 indicates it was built by Holley Co., providing it has a Holley Top. The Zenith-1 was built by Zenith Co. They both use the same jets. Ron

11-25-2017, 06:04 PM	#3
Terry, NJ Senior Member Join Date: May 2010 Location: Bucks Co, Pa Posts: 3,740	Re: Zenith 2 carb REVISION! I was not happy with the readings I got last night in the cold, and with a vernier. Tonight I went back in to do the job right. After screwing around with a couple of carburetors until I got one I could get the butterfly screws out of and remove the throttle shaft. I miked it with a micrometer, not a vernier. Shaft Dia. was .279, that's more like it! I then stuck a 9/32 (.281) drill blank into the bore and shook it around. It was a good fit and I estimated about .001-2 slop so the bore size is .2815-.282 with a shaft dia. of .279 is about .0025 to.003 clearance. I, myself wouldn't bother with oversize shafts or bushings to gain what? Sorry for the confusion last night. Terry

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11-25-2017, 04:34 PM	#1
EdB Junior Member Join Date: Jun 2010 Posts: 27	Zenith 2 carb is the inside diameter on the cap, main & idle jets all supposed the same? The 'A' sat for a long time; I inserted a paper clip thru them to clean & have been experience backfire after running temperature is reached. Thanks.