Old, is it a Komatsu excavator? Sometimes when the alternator goes/gets bad, it will put voltage to its "R" terminal, making it think it is running, thereby not letting it crank. Causes funny cranking problems SOMETIMES. I believe it should crank even if only at 12 volts even. Check both batteries separately, then hook them up together, and verify you DO have 24V. I had one that would crank slow, (PC300), check each battery separate and they were each over 12V and both load tested ok. Hook them together, and could only get 16 volts. Not sure what went wrong inside that one battery as no matter how I checked they came out good separately. I ended taking a different battery up to it and hooking the originals up to that new one. The one that gave me 24 volts with the new battery was kept, the bad have me 16V again, replaced it. Anyway, remove the wire on the "R" terminal of the alternator, see if it then will crank. If so, its about a 99% chance your alternator is junk. There should be no voltage to the "R" terminal or wire going to it until it is running. There is I believe a "safety start" or whatever it is called down near the back of the engine? Bunch of junk that all has to work together/see the right things to start.
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
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 - Third Brush Generators - by Chris Pratt. While I love straightening sheet metal, cleaning, and painting old tractors, I use every excuse to avoid working on the on the electrics. I find the whole process sheer mystery. I have picked up and attempted to read every auto and farm electrics book with no improvement in the situation. They all seem to start with a chapter entitled "Theory of Electricity". After a few paragraphs I usually close the book and go back to banging out dents. A good friend and I were recently discussing our tractor electrical systems when he stated "I figure it all comes back to applying Ohms Law". At this point
... [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.
