My 1994 Autolite catalog shows a 295 as a 18mm, 3/8" reach, standard tip and non-resistor. The 303 is three heat ranges cooler (resistor type) however there is a 292 (non-resistor)which is the coldest plug in the heat range. I would suggest going with the 292 just to remove the spark plug as a possible problem cause. Since you have raised the compression ratio you will likely want to run a colder plug as standard practice and the 303 may be the right plug after you get the problem sorted out.
As others have posted high idle speed can/will promote the run on problem. If you remember many cars in the 70's used a solenoid to set the idle speed. When the ignition was shut off the solenoid allowed the throttle butterfly valve to close off. I am not suggesting you need a throttle solenoid; only to say the idle setting is important.
91 octane fuel should be plenty good for 8.5:1 compression however two octane numbers can make a big difference. If 93 octane is available I would suggest trying it. If 93 octane no ethanol is available then adding 10% -15% of E-85 would kick it another 1 to 2 octane numbers. After that you will need to go with race gas or airplane fuel. Once you find a fuel that actually allows it to shut down without run on you will have an idea of how big or if you have a problem.
The real issue (to me) is what is the compression ratio. Yes the pistons may be 8.5:1 but with what deck height, head gasket thickness, chamber volume.....? Shutting off at idle is one thing but to develop full cylinder pressure at power and not detonate is the bigger concern. Detonation at full power will fail parts - run on at idle sounds nasty but does little damage.
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 - Farmall 460: That's My Girl - by LeAnn R. Ralph. How many sounds can you think of that are as familiar to you as your own breathing? What about the hum of your refrigerator? Or the thump of your clothes dryer? Maybe the engine of your car? You hear those sounds every day, and you don't think much about them, do you. I can think of a few common, ordinary sounds in my daily life, too.
... [Read Article]
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.
