Now, as far as race condition, the engine speed will always, always, always be determined by the volume of air, and fuel being introduced. I'm sure you know this. Look for areas where air may be getting in that is not part of the metered means through the venturi of the carb. #1. Throttle shaft loose in the bore. It is always downstream from the venturi, and causes many vacuum leaks, which are compensated for by making the fuel mixture richer. #2. Intake manifold flange, and gaskets. I'm sure you are using new gaskets, but make sure the flanges are clean and flat. A warped flange will let in a lot of air. #3 Cracked intake manifold. Hard to see, not common but possible.
Read all your plugs. If they look light brown, then the mixture is close, but you are compensating with added fuel for a vacuum leak. ALL the air for the engine must come through the venturi. It is the only way to properly meter the mixture. I would get it started again, then back off the low RPM and the main fuel jets (A and B nuts in the diagram) so that the engine is running as lean as possible. Then, once it is running very lean, use a can or carb cleaner spray on the various parts of the carb and intake to identify vacuum leaks. When you spray on a leak, the rpm will go up quickly as added fuel reaches the engine.
There is also something called a "Gunson ColorTune" that can be very helpful in old engines for setting the right mixture. Can be bought on Amazon or Ebay. Gives a very clear visual indication of correct mixture settings. I use it on old Ferraris to tune each of 12 carb bores, for each cylinder. (and I charge a lot of money too!). Lucky, you have only one carb to adjust.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Sunday Drives - by Cowboy. Summer was finally upon us here in Northern Maine. We have two types of industry up here, one being "Forestry" (Wood Products) and the other "Farming" (Potatoes). There is no shortage of farm tractors and equipment around here! I have been restoring old Farm Tractors for the past 6 years, and have found it easier and less expensive to hit all the auctions and purchase whole tractors for parts needed. My wife who works at a local school, and only has weekends and summers off, while on t
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
