Hi, have 2 NOS zenith carbs on an Edmond's aluminum intake mounted on a 1949 Ford 226 H engine in a sprint car. Motor is rebuilt with milled head, 3/4 grind cam, split exhaust into 2 headers and Mallory dual point distributor. At cold start and at idle engine appears to be running too rich. I am looking for the adjustable main jets for them or a replacement fixed jet smaller than what is there now. Fixed jet is marked 061. Any help would be appreciated!! Thanks.
Hi, yes I did. About 2 psi feeding carbs. Have a hand pump with a gauge running about 1.5 psi and also have an electric low pressure fuel pump in case riding mechanic is not able to pump fuel. Installing a pressure regulator as we speak and setting it to 1 psi to see if that helps! Learning the zenith carb.! What would be max pressure it could tolerate? I have the original carbs that came with the manifold and should check out the fixed jet to see if someone reduced the size. Those carbs do not have the adjustable jet assemblys. Do not know if these 2 carbs are too big for the motor? Belong to a vintage race car group so racer will see exhibition racing only and not aggressive track time.
What are the tag numbers on the carburetors? What is your vacuum reading at idle? What is the idle mixture setting? Post-WW-II Zenith downdraft carbs should easily withstand 4~5 psi fuel pressure at idle, more at higher RPM. Not knowing the tag numbers means I am totally guessing, but most of the post-WW-II Zeniths have a vacuum power circuit. Too low vacuum will trigger the vacuum power circuit, and the engine will be extremely rich. Jon.
O.K. Looked over the NOS carbs. On tag riveted to tops F600 F223 outer ring 109918 inner ring. 1 3/8 inch base bore where it fits on manifold. Fixed main jets .061 Float level correct. Dug originals out from storage. Whole assembly unit was on another old race car from the past, removed and hung up for posterity. As follows Front Carb. 95088 H outer ring 9604 inner ring. 1 3/8 inch base opening where it meets manifold. Fixed main jet 021. Rear carb 2192373 outer ring 10528 inner ring. 1 1/2 inch base bore where it meets manifold. Fixed jet again 021. Could not get vacuum reading when I started her as the damn car makes so much noise from the exhaust (loud) it will rattle the windows. Black smoke comes out of both header pipes at the back (rich!!) Have to razz her to clear her throat. Live in a residential neighbor hood and houses are close to each other so will fire her up soon and test vacuum when everybody goes to work!! As far as mixture setting believe I set it as prescribed from text online. Maybe I do have low vacuum! Will have to see. Thanks for the input.
10991B - application Continental 6-226 INDUSTRIAL (read basically constant speed) engine 25mm venturi. 9604 - application IHC GD-214 (6-214) 26mm venturi 10528 - application GMC 6-248 29mm venturi Best advice I can give is to read the 2nd paragraph in my signature block. And wish you luck! Jon.
I used 2 factory '54 GMC electric choked Zeniths on a hydro equipped 100 series pickup for 10 years. Cold Ellis intake, iron headers. Never had 1 minute's trouble in Idaho weather, year round service.
Two key points in this post: (1) the two carbs were identical (2) the carbs were designed for an engine used with variable RPM Jon.
O.K. Well All carbs I have are not suitable for my application. That settles it, Thanks for the reply!!
Donald - Zenith made a number of 228's for G.M.C. trucks with a 228. Holley made some 847's for I.H.C. trucks with a 214, and a lot of 1904's for 220 engines. The Holleys have the advantage of tuning jets being readily available. (Opinion) while adjustable main jets are the cat's meow on a single carb application, they introduce a totally new degree of difficulty with a multiple carb set-up. Would suggest NOT using adjustable jets unless you have a good A/F meter. If you wish a suggestion, I would personally use Carter W-1's from a 216 Chevy: 420s (7/8" main venturi) 483s or 574s (15/16" main venturi) The Zenith 228, Holley 847, and Holley 1904 have vacuum power systems. The Carter W-1's have mechanical power systems, which are MUCH easier to tune. If you use the 420s, use two of the 420s. If you use the 483s or 574s; they may be mixed or matched. Identical calibration, with only a slight casting change as a difference. These are pretty common carbs, and since the original application was Chevrolet (1941~1948), parts are readily available. Jon.
Hi, Thank you for the reply. Going to have to rethink whole intake set up for now but will keep your info in case I go this way. Can you give me a ball park figure for 2 carbs for my application? Appreciate your expertise as you are very knowledgeable in your field which I admire, Don.
Don - would need to discuss your engine modifications, and the size and type of tracks you frequent to make a recommendation of either the 420s or the larger carbs. If you decide to go this way, give me a call during my normal telephone hours. Absolutely no obligation. Jon.
Hi, will do. Motor was fired up three times to make sure temp,oil pressure, clutch operation and leaks etc.works since refresh so no time on motor and only warmed up once. This has been a a 9 year restoration and in final stages of body work. Have details of motor work. As far as tracks again it will be used for exhibition racing only (not full out racing!). Track size will vary from a bullring 1/4 mile to about 5/8 .Our club puts on shows all over Northeast. If present carbs are not suitable ( as we discussed) for my application, I will see what they are worth. Thank you again.
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