chorusguy 227 #1 Posted May 10 A little background. Last year, after having sat, I had no spark. Rewired virtually everything. New points, condenser, New coil, New spark plug, swapped out the regulator from a working tractor and she eventually got spark and ran fine. Was using it the other day, and it shut off. Now I have no spark. I have 12+ volts everywhere. But I don't know much about what I should have and when. I have 12 + on the ac lines on regulator, 12 + on positive side of coil and on output of coil, 12 v+ on voltmeter. 12+ between neg and pos on coil. When I try.to start, voltage drops to about 10 on the coil output to spark plug. The battery ground was loose but I tightened it and am getting 12 volts when I connect there to the battery positive. What am I missing? I've tried to look at the spark plug when rolling over but can't get it to a place where I can see. Share this post Link to post Share on other sites
chorusguy 227 #2 Posted May 10 Oh, when it stopped, I saw that one of the ac wires had fallen off the regulator and ground out to the voltmeter bracket. I ordered a new regulator and have that in place Share this post Link to post Share on other sites
Achto 27,565 #3 Posted May 10 (edited) 5 hours ago, chorusguy said: What am I missing? The voltage regulator has nothing to do with engine spark. At least until the battery goes too low to power the coil. First thing I would try is to is clean the points. Turn the engine over till your points are in a closed position. Pry them open and work a piece of 400 grit or finer paper through them a few times. Then do the same procedure using a dollar bill instead of the sand paper a couple of times. If you have a multi-meter - Disconnect the coil "-" wire that goes from the points to the coil, set your meter to check ohms, with the points closed you should have continuity from the "-" wire to engine ground. If you do not, clean the points again until you do. Edited May 10 by Achto 5 Share this post Link to post Share on other sites
Handy Don 12,212 #4 Posted May 10 55 minutes ago, Achto said: The voltage regulator has nothing to do with engine spark. At least until the battery goes too low to power the coil. 1 hour ago, chorusguy said: new regulator and have that in place So now you likely have a good spare! 2 Share this post Link to post Share on other sites
wallfish 16,994 #5 Posted May 10 Clean points contacts, condenser on the - side of the coil You can rotate the engine by hand until the points are in the fully closed position (If they aren't already), then turn the key to RUN, not to start. Now you can manually flip the points open and closed to simulate the engine rotation and easily watch for spark. 1 2 Share this post Link to post Share on other sites
chorusguy 227 #6 Posted May 10 Ok. Thanks for the replies. Rained out at the moment, but will give it a shot tomorrow. Grateful for your help! 1 Share this post Link to post Share on other sites
953 nut 55,188 #7 Posted May 10 If what John @wallfish doesn't result in a spark you may want to remove the condenser lead and try again. 1 Share this post Link to post Share on other sites
chorusguy 227 #8 Posted May 11 (edited) Ok. Cleaned the points. Unhooked the negative coil wire and when I check between the negative points wire and the negative battery terminal I'm getting a reading of .3 ohms with meter set at 200 ohms. It dances around quite a bit before it settles. With the key in run, it dances a bit more but still settles at .3. Not seeing any spark at points. Also checked with positive wire on coil disconnected. Still seeing no spark. Edited May 11 by chorusguy Misspelling Share this post Link to post Share on other sites
Handy Don 12,212 #9 Posted May 12 (edited) 7 hours ago, chorusguy said: Ok. Cleaned the points. Unhooked the negative coil wire and when I check between the negative points wire and the negative battery terminal I'm getting a reading of .3 ohms with meter set at 200 ohms. It dances around quite a bit before it settles. With the key in run, it dances a bit more but still settles at .3. Not seeing any spark at points. Also checked with positive wire on coil disconnected. Still seeing no spark. If I understand your hookup and you’ve got clean connections with your meter, there should not be ANY resistance. 0.3 ohms in a 12v circuit is actually quite a bit. I=V÷R so a 40 amp loss. You have at least one seriously bad connection somewhere in that circuit. Edited May 12 by Handy Don Share this post Link to post Share on other sites
chorusguy 227 #10 Posted May 12 Ok. Great. I had a loose ground from the battery to the frame, but fixed that I think. However, I watched a video today and it intimated that lack of spark could be a bad ground or an unexpected ground somewhere. Does that make sense? Share this post Link to post Share on other sites
Handy Don 12,212 #11 Posted May 12 1 hour ago, chorusguy said: Ok. Great. I had a loose ground from the battery to the frame, but fixed that I think. However, I watched a video today and it intimated that lack of spark could be a bad ground or an unexpected ground somewhere. Does that make sense? Yes, for sure. A bad ground means that the juice cannot complete the circuit from the plus to the minus of the battery. For spark that circuit is typically from battery plus to ignition switch, to coil plus then coil minus, to points, to ground, and finally from ground to battery minus. WH treats the entire frame and engine block as ground and relies on them all being electrically connected. In your case, either the points are not well connected (electrically) to the block or the block is not well connected (electrically) to the battery minus. Share this post Link to post Share on other sites
rmaynard 15,434 #12 Posted May 12 I don't think you mentioned what year C-160 auto you are working on. There are different wiring diagrams for each. Some have a straight path from coil to ignition switch, others go through a PTO safety switch. Share this post Link to post Share on other sites
chorusguy 227 #13 Posted May 12 Think it is a 74. No safety switches. I think must have a ground issue Share this post Link to post Share on other sites
chorusguy 227 #14 Posted May 20 Ok. I've been out probing with my meter. Battery is over 12 volts, starter relay is 12 volts, points structure is 12 coil is 12 (plus minus and output) ammeter is 12, regulator is 12. Some of these are tested in run, some in start. I don't really know what I'm doing so a bit of a crap shoot. The only place I'm getting less than 12 volts is on the switch in start and the coil to sparkplug outlet they are both around 8. Bad coil???? I'm sorry I'm so ignorant about this. Share this post Link to post Share on other sites
chorusguy 227 #15 Posted May 20 ok. I got it running. Replaced the coil and points with an old set and it runs. Now, somehow, I have fouled up the key switch part of the circuit. Pray for me. 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,040 #16 Posted May 20 Sounds like you have a Kohler engine. One with a over-head valve Tecumseh was also available. Click on the tractor for more info Share this post Link to post Share on other sites
chorusguy 227 #17 Posted May 20 I do have the kohler. I think I shorted the switch, so have ordered another one. Thanks for the help. Share this post Link to post Share on other sites
