While working on 3 different 8Ns today, and having starting problems with all of them, and freezing my tail bone, but still having some body heat in the brain, I came up with this "new" theory...well, new to me.As I have worked on 8Ns on an occasion basis for the past 35 years, I have gained a lot of experience, mostly from the school of hard knocks. In most cases, non starting can be traced to one item, sometimes carb, sometimes points, etc. By careful diagnosis, I have kept the parts bill reasonably low, and have maintained a good running tractor. But, either I am losing it, which at age 60 is a possibility, or I am in need of a new theory to explain why I can't come up with a clear diagnosis, and provide a simple mechanical solution to "gett'er done". One of these Ns is mine, and has been a favorite for 35 years, so it doesn't fool me too often. The other 2 Ns belong to 2 different neighbors, but I have been their chief mechanic for 5 to 10 years. I have worked a bit on Peter's 8N on/off for a couple of days and finally got it to start on ether, and then it would keep running. It is 12v with a Delco alternator. It is the nicest looking tractor of the 3, but it experienced a great misfortune 2 summers ago when Pete got caught plowing his garden near the creek and one whale of a thunderstorm let loose. Pete bailed off and ran for the barn just being missed by some close bolts of lightening. Normally, that is the smart thing to do...but the rain just kept coming, the creek rose to a never before height, and by morning there was a loon perched on the 2 or 3 inches of steering wheel that was above water. We waited a couple of days for the water to go down to where we could walk out to the submarine N, instead of swimming to it. I hooked up a long cable to its hitch and pulled it out of the temporary 10,001st Minnesota Lake with my ZB Moline. Pete felt real good to get his tractor back from the evil jaws of the swamp monster, and the Moline felt real proud that it had saved something as valuable as a late model 8N. The 8N had tried real hard, but had failed its first swimming lesson. So we pulled it back to my barn and shop, drained all the oils, air cleaner, changed the points and condenser, cleaned out the gas tank, and removed one large snake that wanted to live inside the gas - hood cover. I got her running, even fairly reliable in starting, but advised Pete that due to the swamp water and likely corrosion, that there could be a few more problems to deal with in the next few years. So it was no big suprise, when Pete called a couple of weeks ago, explaining that his N needed some help to get it started...he just could not get her to even fire, but it turned over till the gas was dripping out of the carb, and finally (or maybe soonly) the battery just gave up. So I drove over to his place with the truck and a tow strap, and led her back to my shop, like bringing a lost horse back to the paddock. Charged the batt back up, and cranked with no fire, even with a few squirts of ether. It wasn't turning very fast, so I load tested the batt...very weak. (Same batt that had been the new queen size bed of the swamp snake).. Battery marginal. Well it was time to go NAPA and get a new battery and replacement batt cable (cable marginal due to corrosion beneath the insulation), and installed them. OK, now it cranks like it should, but no start! Pulled the dist cap and rotor and checked the points...not too bad, just the usual electrical pitting, but I cranked it with the cap off and watched the point spark. It looked too big, but very yellow in color...marginal point spark. Put the dist back together with new points and condenser. Crank, crank, crank...no start. I took a new spark plug and hooked it up to one of the plug wires...good blue spark. So I got out the penetrating oil to soak the rusty base of each spark plug and then carefully worked them back and forth until I had those 4 stinkers out. They didn't look too bad, but were just marginal, a bit wet, all black, but no fried on oil residue. OK, new plugs! Crank, crank, crank, no start... now a few shots of ether...she starts!! Oh the relief! I drive it around the yard and run it for about 15 minutes, OK!! And then shut it off. I came back to it about 1/2 hr later and crank, crank, crank,... no start. Oh damn! A couple shots of ether and a few short cranks, and she fires up and runs nicely....Dang! Shut 'er off again. Pete stops by to see how it's going. I stuck my finger into the throat of the carb to show him where I was shooting the ether, but my finger came out full of gritty rust. How it even ran is beyond my feeble comprehension. My gosh, that carb is marginal! I pulled the carb, disassembled it, scraped a bunch of rust from the float bowl and passages, and tossed it into the carb cleaner solution for the night. Tomorrow the carb will be spiffy with new gaskets, needle and seat, and clean innerds. The little spring on the choke plate window had rusted through, so the choke had almost no affect in helping it start, as the window was hanging wide open. I hope I can find a replacement spring. Maybe it will then start with reliability and vigor. So while I am working on Pete's N, Mark (a special needs adult) calls my wife about the 6th time today to tell her that his 8N won't start. She gently pleads with me to go and fix Mark's tractor, so he'll maybe stop calling. So after a warmmer upper cup of coffee, I am off in the snowplow truck to Mark's house, carrying the usual toolbox and jumper cables. Mark's tractor is in the shed, amidst the usual piles of stuff. So I test the batt with multimeter... about 11.2v... now that is marginal, and darn near dead. So we get an extension cord and batt charger hooked up and head up to his house where his mother has just pulled some really excellent Christmas cookies out of the oven. It's like I died and went to heaven, with those cookies and a chance to warm up. Being a very nice lady, she presents me with a Christmas present for helping Mark... a John Deere clock that has the putt-putt sound every hour on the hour....Oh Lord, I didn't go to heaven, I'm back here on Earth and I've got to listen to 2 cylinder JDs until the batteries die, which I hope is soon. Poor lady, she means well, but I just don't do Deeres, but I assure her that it will make a nice addition to my shop, where I really need a clock. Back to Mark's N. Charged batt, less than 18 months old, 12v. Hey, this tractor has always turned over really easily (probably needs rings).
Turn the key, hit the start switch, she cranks a bit, almost fires on a couple of cylinders and quits..like the battery is dead. Oh heck, move that pile of stuff and make room for the snowplow truck to get close enough to jump start the N. Got 'er hooked up, but really pulled hard on the truck's 130 amp alternator. Gave it a few minutes to charge up and cranked it with the jumper cables still hooked up to the truck battery. Dang! It sure cranked a lot slower than usual, but almost started. Well, whatever, I'll get a new battery for this N on Monday. But, I'm betting that the new batt will be pulled down real quick, and that the real culprit is the starter motor. Mark said that he saw "that red round thing" smoking a few days ago when he was cranking away on it. Well it didn't do any smoking today, but it sure wasn't turning the engine over very fast, even with the truck jumpers on it. So, I think we got a real marginal starter motor (probably cooked by Mark refusing to give up cranking away on it). So I went up to the house (another cookie or two??), and tell his Mom to be prepared for the costs of a new battery, and likely a starter rebuild. I throw the tools and jumper cables in the snowplow truck and head home. OK, it is time (a little daylight left) to jump on my 8N with the 7 ft rear blade and clean up a bit of now wet heavy snow from the front of my barn. Oh YES, it starts, just like a faithful dog greeting her master. It feels good to move a little snow, I can see what I am doing, unlike plowing in the truck, where you are just hoping not to scrape too much gravel, or scrape something else while trying to clean up close to stuff. About 5 minutes later, I've killed the engine while backing over a pile the blade has just pulled. No sweat! Just hit the start button...what...it doesn't even turn over! So much for the faithful dog thing! Walk to the shop and get a hand full of wrenches to tighten the batt cable post connectors. Yup, the neg one was a bit loose (dang...a marginal connection... but it had started easily just a few minutes before). So I hit the start switch a few times and could hear the solenoid click with a good snap, but no other response. Took off the gloves, and started feeling the wires and connections for the tell tale heat of a high resistance connection. The copper bar between the solenoid output and the hot terminal of the starter motor was warm, but I had never had that off since the overhaul in the mid 70's. But the 2 nuts were a bit loose... a couple marginal connections. Like Dell always says...shiny and tight! So gave the copper a shine with emery cloth at the ends, cleaned up the nuts, washers, and gently wire brushed the copper bolt threads. Put the bar back in place and snugged up the nuts, hit the start switch....and she was back to being my faithful one, once again. Now the developing theory of Multiple Marginalities. As a retired science teacher, I realize that no good theory is developed from only one set of data. But now, today, I had 3 different sets of data that suggested the following theory: Although a single item or failed part can and usually does cause a "no start" problem, the sum of a number of marginal items occuring simultaneously can cause the same "no start" condition. This shall be known as the THEORY OF MULTIPLE MARGINALITIES. I do hope that you enjoyed this, and find it useful someday. Keep 'em crankin! Paul in MN
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