Lman 14 #1 Posted October 22, 2022 (edited) I'm trying to restore my first lawn tractor, it's a 1975 A-80-E with a Tecumseh VM80 engine. Starter motor works, engine turns over but does not fire. New spark plug gets wet, but does not appear to spark. I downloaded everything useful I could find, but I don't have all the tools. Before I take the flywheel off to check the points, what other things should I try? Is there an ignition cut-off wire I can try and disconnect? I have a hard time understanding the wiring in the picture below. What does it all do and where is (+) and (-)? Edited October 22, 2022 by Lman Share this post Link to post Share on other sites
ri702bill 7,344 #2 Posted October 22, 2022 I believe that is the diode setup for the charging system.... 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #3 Posted October 22, 2022 1 1 Share this post Link to post Share on other sites
Lman 14 #4 Posted October 22, 2022 (edited) Thank you very much, so that's the battery charger. Much obliged for the wiring diagram, that's gold! Dad and I used this mower for years without a battery. If only we knew we should have removed the diodes. Could not doing this have caused damage? Edited October 22, 2022 by Lman Share this post Link to post Share on other sites
Lman 14 #5 Posted October 22, 2022 (edited) I should correct the topic title but I don't think I can. The spark plug does seem to produce a spark, but the mixture in cylinder does not ignite. I'll try spraying some carb cleaner in, haven't got that yet, see if it fires up. There might be some stale fuel or gunk in the carb. Edited October 22, 2022 by Lman Update 1 Share this post Link to post Share on other sites
953 nut 51,775 #6 Posted October 23, 2022 6 hours ago, Lman said: There might be some stale fuel or gunk in the carb. I think you have the right idea. Rebuilding the carburetor will probably do wonders. If you had been using gas with ethanol in the past I would suggest replacing the fuel line, fuel filter and rebuilding the carburetor. Ethanol has killed many small engine fuel systems. use this site to find real gas in your area. https://www.pure-gas.org/ 1 Share this post Link to post Share on other sites
Lman 14 #7 Posted October 24, 2022 On 10/23/2022 at 2:01 AM, 953 nut said: I think you have the right idea. Rebuilding the carburetor will probably do wonders. If you had been using gas with ethanol in the past I would suggest replacing the fuel line, fuel filter and rebuilding the carburetor. Ethanol has killed many small engine fuel systems. use this site to find real gas in your area. https://www.pure-gas.org/ Success, it's running again! 1 Share this post Link to post Share on other sites
