chipmonroe 2 #1 Posted October 4, 2020 (edited) Guys- first post; thanks for the site. I have a mid 80s 520H (Onan P220g) that's been a faithful tractor for quite awhile. It has been mowing grass and pushing snow at the same house with me being the third owner. This summer all of the sudden it wouldn't start. The motor would just turn over and over but not fire. It stayed at a local shop for awhile before they gave up on it. Then I figured I'd give it a go myself. I think the engine is not getting enough spark. When I hook a sparkplug tester to it there's a glow in the tester but it's really dim. A friend of mine who is much braver held one of the plugs with a towel, turned the motor over, and there was just a tiny spark. The demystification guide just goes based on "spark" or "no spark" but I think mine is in between. I've measured 6 ohms across the coil, higher than it should be. Should I replace the coil? Or do something else? Thanks in advance... Edited October 4, 2020 by chipmonroe addition of engine model 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,376 #2 Posted October 4, 2020 I wonder if the ignition module/ pick up rotor behind the flywheel is actually going bad causing the weak spark but the coil could also very well be going bad... eBay has cheaper alternatives...https://www.ebay.com/itm/183351368364 ... here's the ignition module kit ...https://onanparts.com/index.php?main_page=product_info&cPath=1_16&products_id=737&zenid=b7f5a17c4b2821b1ac6c2f728cda3bed. BTW the first year 520H was 1988 and had the straight front axles '88 and '89 then 1990-97 had the swept forward front axle for the 60" decks plus the gear reduction steering gear. Then there were the HC commercial versions and the rare (200 or so) 8 speeds. 1 Share this post Link to post Share on other sites
lynnmor 7,904 #3 Posted October 4, 2020 I guess you saw the thread about Onan spark just above your post? It does appear that you need a coil if you did all the checks for it and the ignition module. If you buy a cheap coil kit, the Chinese parts may not include the installation instructions, see this thread for information. Did you check to see if the engine is getting gas? An easy test is to dribble a teaspoon of gas down the carb and then quickly run the starter, if it briefly fires you may have fuel delivery issues. Just an additional test to rule out ignition problems. Ohm meters can give erroneous readings. 1 Share this post Link to post Share on other sites
chipmonroe 2 #4 Posted October 4, 2020 Thanks guys. I'll replace the coil and see how it does. I think it's getting gas because I can see gas in the line filter. But I'll try that while I'm waiting on the coil to arrive. I've got time- mowing season is over and snow season has not begun... Also thanks for the year- the previous owner said it was an 86 but it must be an 88 or 89. 1 Share this post Link to post Share on other sites
