Commonly Asked Questions About Old Deeres

What are some of the most common questions asked in the Mr. Thinker column in Green Magazine? Here’s a sample.


First, the questions:

Question 1 About a year ago, I completely restored a model “M.” I thought that I had done a good job until I noticed that the engine always seemed to run hot. Since that time, I have completely torn the engine apart (again), soaked it in a hot tank and then removed any remaining scale and rust from inside the water jacket with a specially made, long handled dental scraper. I also bought and installed a brand new radiator. I got it all back together, added coolant and then watched in abject horror as the needle on the temperature gauge slowly crawled right back up to “HOT.” I’m about to call Doctor Kevorkian. What did I miss? What should I do?

P.B., Minnesota

Question 2 What color should my horse drawn corn binder be?

B.F., Oregon

Question 3 My John Deere “B” has a brass tag. I say that means it is worth more than my friend’s tractor that has an aluminum tag. He says it doesn’t. We have bet a six pack of Zima on your answer. Who is correct?

P.M., New York

Question 4   My John Deere “A” doesn’t have a serial number tag. Is the number printed on the tractor anywhere else? If not, I know what dealership it was sold at—is there any way to trace it through them?

T.S., Missouri

Question 5 Can you tell me how many model 70 diesels came with wide front axles?

M.K., Ohio

Question 6 Since you can now get only unleaded fuel, should I put a lead additive in my 520’s gas?

H.H., Texas

Question 7 I’m having a problem with spark plug fouling on my “G.” I had the magneto rebuilt, but after running five to 10 hours, it won’t start unless I put in a new set of plugs. What could be the problem?

H.C., Pennsylvania

Question 8 What kind of engine oil should I use in my just overhauled 1947 “A”? Some of my buddies say that I should use non-detergent, since that is what the engine was designed for.

M.S., Florida

Question 9 I’ve been a subscriber to Green Magazine for many years and I’ve never seen pictures or mention of the 720s that came out new with green and white paint. How come?

S.O., Georgia



Then the answers:

Answer 1 What should you do? Stop looking at the gauge. This was a problem on the model “M” that Deere and Company realized 60 some years ago when it changed the location of the temp gauge indicator bulb from the water outlet manifold to the water jacket at serial number 45409. Most likely, your tractor isn’t running as hot as it would like to lead you to believe. MT


Answer 2 The basic color scheme for Deere horse drawn equipment is green metal, yellow wheels and red wood, the red being something close to International Harvester color. Yes, you will see illustrations in some old catalogs of machinery painted differently, but no one seems to know for sure if these machines were “dolled up” for the catalog or if every plow, cultivator and potato digger received that much attention to cosmetic detail. MT

Answer 3 The only difference in your tractors is that one has a tag made of an alloy consisting of copper and zinc and the other from a silvery white ductile metallic element. If there is any difference in value, it is only because of the perception by others that brass tagged tractors are more rare or special. Zima? What’s wrong—Fresca too strong for you guys? MT


Answer 4   If you wanted a tractor with a serial number tag, you should have bought a tractor with a serial number tag. The serial number isn’t printed anywhere else on the tractor. As for tracing it through the dealership that sold it, if you know who the original purchaser was and if they are still in business and if they have records that go back over 50 years, you might be in luck. MT

 Answer 5 No. For numbered series tractors, with few exceptions, Deere records show only type (row crop, standard etc.), fuel type, build and/or ship date and destination. Options aren’t shown, especially those like front axles, which could have been changed anywhere between the factory and the farmer. MT


Answer 6 If it will make you sleep better at night, sure—go for it. Or if you live in Death Valley and use the tractor hard, eight hours a day most of the year and it doesn’t already have hardened valve seats. Otherwise, it’s a waste of money. Most collector tractors will never work hard enough to cause valve recession. Spend the money on a couple of new screwdrivers; you can never find the right one when you need it anyway. MT


Answer 7 First of all, if you are running Champion plugs, try something else. Mr. Thinker doesn’t know why, but for decades, Champion plugs have been infamous for fouling. One would think that a company as big as Champion would have figured out and corrected the problem by now. If you aren’t using Champions, switch to a hotter plug with whatever brand you are using. Fouling occurs when carbon deposits on the plug and provides the electrical charge a pathway to reach a ground without having to jump the gap to the electrode and cause a spark. Carbon is formed when the engine is running too rich or when the engine burns oil. So get your carburetor rebuilt. If that doesn’t help and your engine takes oil, new rings and/or valve guides may be your next need. MT


Answer 8 There are a lot of schools of thought on this, but since you asked Mr. Thinker, his opinion is that if the engine has just been overhauled and is presumably clean with new gaskets and seals, it is fine to run detergent oil. Anything from straight 30w to 10w40. If you have recently bought an older tractor that just needs a tune up and you have no idea of its oil history, you might consider staying with non-detergent. Before you ask about synthetic, Mr. Thinker will answer with “possibly” in an overhauled engine, but “never” in an engine that hasn’t been apart in years. MT


Answer 9 You are more likely to have Mr. Thinker mention Sasquatch, the Loch Ness monster or El Chupacabra because there is more evidence that they exist. You can tune your television into the Discovery Channel or TLC almost any night of the week and see a show about them along with some grainy photographs or video. Mr. Thinker has told numerous people who claimed green and white 20 series tractors existed to send him a piece of Deere literature that shows them. Or maybe a family photo from when Grandpa’s brand new green and white 620 was delivered. He’s still waiting. These people are inevitably from the southern U.S. Could it be that climatic conditions there cause the yellow to fade to white? MT