JRess 12 #1 Posted May 2, 2020 Hi everyone, brand new to this group and to tractors of any make or model. Picked up a smoothly running C-121 and it has been starting and running with no issues. Went to start this morning, turned over and caught then died. I get no response when turning the key, no click no nothing. Thought it might be the ignition switch (primarily because aside from jump starting that is the extent of my ability in troubleshooting), changed it out but no luck. Any suggestions? Please know that while I am mechanically OK, as far as how electrical systems and motors in general work I am clueless. Couldn't even tell you what a starter looks like, although I am sure I can find some manuals on this site. Thanks in advance, headed back out to use a wheel barrow. John 3 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #2 Posted May 2, 2020 Welcome to the forum. Download these 4 pages. Have a test light or voltmeter? Garry 2 Share this post Link to post Share on other sites
ebinmaine 71,916 #3 Posted May 2, 2020 John... No worries. We'll get your tractor fixed right up. What do you have for tools? Test light? Voltmeter? Good sense of adventure? Share this post Link to post Share on other sites
JRess 12 #4 Posted May 2, 2020 re adventure I have to admit at 63 I do continue to amaze myself. I work at Lowes and can pick up either or both. I assume for voltmeter just need something basic? After a day of moving rocks with a wheelbarrow and pick up I find myself motivated. 2 Share this post Link to post Share on other sites
ebinmaine 71,916 #5 Posted May 2, 2020 49 minutes ago, JRess said: re adventure I have to admit at 63 I do continue to amaze myself. I work at Lowes and can pick up either or both. I assume for voltmeter just need something basic? After a day of moving rocks with a wheelbarrow and pick up I find myself motivated. Buy an inexpensive volt/ohm meter. It'll be handy for things. Share this post Link to post Share on other sites
JRess 12 #6 Posted May 3, 2020 I now have a test light and volt/ohm meter but no more knowledge than before. Any direction appreciated! 1 Share this post Link to post Share on other sites
ebinmaine 71,916 #7 Posted May 3, 2020 Well. Let's see. First we need to verify that the old ignition switch and the new one MATCH. Make sure that both are identical and have the identical terminal letters on the back. This is being brought up because the new replacement switches very often have an M terminal when the older ones should have had a B terminal. Another thing that could be tried is to jump the solenoid. See if you get juice that way. Also, you need to verify that your safety switches are doing what they should be. These systems are DC. Direct current. That means you need to be sure that your grounds are in good condition. Bad ground at any given point in a circuit will make, no circuit. @953 nut, @pfrederi. Richard and Paul, what can you add to this? Share this post Link to post Share on other sites
953 nut 59,323 #8 Posted May 3, 2020 John, couple of questions, is the PTO lever pulled back toward you? Is the clutch pushed in? With any electrical problem the first thing you need to do is clean and tighten ALL electrical connections including grounds. That alone will clear up most problems. The voltage to your starter is switched by the solenoid. The voltage that operates the solenoid comes from the battery "+" terminal, through one of the large posts on the solenoid, Through a fuse holder with a 25 amp fuse, then to one of the terminals on the amp meter, through the amp meter, then on to the "B" terminal of your ignition switch. Use the meter or test light to check there points for voltage. Connect one lead to the battery "-" terminal and use the other (meter set to DC) to check for 12 +/- volts at each of these points in the order I have listed them. If you have 12 volts all the way to the ignition switch then turn the key to the start position to see if there is voltage to the "S" post of the switch. Let us know what you come up with and we can go from there. Share this post Link to post Share on other sites
JRess 12 #9 Posted May 5, 2020 Thanks guys, been a busy couple of days. I will have time to try your suggestions tommorow after work. I did make sure the replacement ignition switch matched the old. 1 Share this post Link to post Share on other sites
ebinmaine 71,916 #10 Posted May 6, 2020 2 hours ago, JRess said: Thanks guys, been a busy couple of days. I will have time to try your suggestions tommorow after work. I did make sure the replacement ignition switch matched the old. Nice. No worries man. Keep us posted..... Share this post Link to post Share on other sites
JRess 12 #11 Posted May 11, 2020 Gentlemen: I was wrong, while the new ignition was configured just like the old, the new switch does have an M terminal. I cleaned the terminals on the old and reinstalled, nothing. I jumped the solenoid and got the starter to turn over. Took a deep breath and fired up the multimeter and started checking different points. Really in the dark as to how to interpret where I was getting a good reading and where I wasn't. Tried to get a reading off the S post on the ignition switch and got nothing. Pulled the panel to access the ammeter and got good readings. Looked for but could not find the 25 amp fuse (is it in-line covered with black casing and electrical tape). Now I went off the reservation and thought to see what I would get at different points by fully engaging the ignition switch. I am sure at this point you are shaking your heads. Well dammit it started. Put everything back together and it still starts. I can't say I have learned alot but I appreciate the person that loaded the schematic and both of your input. I am sure I will be back, but in the meantime enjoy your spring. I have rocks to clear. Thanks again, John 1 Share this post Link to post Share on other sites
SylvanLakeWH 28,122 #12 Posted May 12, 2020 (edited) Sounds to me like you have a short somewhere that you jiggled right while diagnosing the issue... Back to @953 nut‘s point - clean and tighten all electrical connections, including grounds... Edited May 12, 2020 by SylvanLakeWH 1 Share this post Link to post Share on other sites
rmaynard 16,212 #13 Posted May 12, 2020 C-121 and all of the other horses with a cradle-mounted engine are notorious for having intermittent grounding problems. The engine is isolated from the frame with rubber mounts. Therefore the mounting cradle has it's own ground wire connecting it to the frame. That is the first place that I would look when trying to diagnose any electrical problem. No ground, no voltage. Starter, solenoid, coil, etc are all engine mounted, are all dependent on that ground wire to complete the circuit. I had a C-101 that every time I would try to start it, the throttle cable would get hot and smoke. Turns out that the ground wire was poorly connected and the starter was grounding through the throttle cable. 3 Share this post Link to post Share on other sites