stevebo-(Moderator) 8,041 #1 Posted November 20, 2014 All- I have an 89 520H that turns over but has no spark. Can anyone tell me where to start? If any of the switches are the problem will it turn over with no spark? Anyone have any pointers ?? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #2 Posted November 20, 2014 Detailed wiring diagram The only thing the starter circuit and ignition circuit have in common is the ignition switch is powered by the same 20 amp fuse so it must be OK. They also share the ground at the engine. Ignition switch in RUN or START powers one of the pto switches. Pto OFF that switch powers the ignition coil. Pto ON the seat switch powers the ignition coil. They also share a 5-pin connector but use different pins. To check backwards see if you have power at the ignition coil yellow wire in Run and Start. Garry Share this post Link to post Share on other sites
baerpath 517 #3 Posted November 20, 2014 Run a jumper wire to the positive battery to positive coil terminal and see if it fires. That will bypass all the wiring. Then you will know what way to go Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #4 Posted November 20, 2014 Garry and Duane. Thank you very much. I will mess with that today. Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #5 Posted November 27, 2014 If the oil pressure switch is bad or the oil level is too low would that cause the motor to turn over but no spark? I failed to check the oil and it was pretty low and parked on a hill so maybe that caused a low pressure indicator to light. Share this post Link to post Share on other sites
km3h 543 #6 Posted November 27, 2014 Steve, low oil is never a good thing. Top it off and see if it starts. If not, then do as Baerpath said. Run 12 volts from the positive batter post to the positive side of the coil. If it doesn't start then we can go to the next step. Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #7 Posted November 27, 2014 I will try that this weekend. Share this post Link to post Share on other sites
Geno 1,928 #8 Posted November 27, 2014 Low oil won't interrupt the starting or running circuit on that one like some of the older ones. Yours has a simple sending unit that grounds the lamp if it's low. Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #9 Posted November 27, 2014 Thanks geno that is what I thought. The light will just go on if low right? Share this post Link to post Share on other sites
Geno 1,928 #10 Posted November 27, 2014 (edited) Yep, it gets power directly from the switch. Edited November 27, 2014 by Geno Share this post Link to post Share on other sites
shallowwatersailor 3,213 #11 Posted November 27, 2014 I had a No-Start situation with my 1989 520-H earlier this year. Parked it in January and it wouldn't start in June. Using a spark tester inline with the sparkplug, I would only get a spark when I stopped cranking and turned the key off. I shook my head for a while. It turned out to be a bad ignition switch. Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #12 Posted November 27, 2014 Just in case I ordered a new switch on ebay. Share this post Link to post Share on other sites
Geno 1,928 #13 Posted November 28, 2014 You can bypass everything by running a jumper from the battery pos directly to the + on the coil. If it starts you'll know it's before the coil, if not it's after. I like splitting the system in two to find out what direction to go with when I start testing. Most problems on those do end up at that white 9 pin connector though. 2 Share this post Link to post Share on other sites
stevebo-(Moderator) 8,041 #14 Posted December 1, 2014 I finally spent a little time on this today. A PO bypassed the pto lever switch. There there two wires that were four wires (orange, yellow, tan and green I think) They came lose and once I looked the the wiring diagram I figured out which ones were crossed. connected and crimped the correct wires back and she fired right off like it is used to doing. Now I need to mount the smaller tires with chains and get ready to push some snow with it. 2 Share this post Link to post Share on other sites
Olratlr 25 #15 Posted December 3, 2014 I had the same problem 1995 520 H it was the ignition module behind the fly wheel. Hope this helps. Share this post Link to post Share on other sites