jst 0 #1 Posted February 10, 2015 I have a 520h with a Onan 20hp that will not start. Started fine when I put snowblower on a couple of months ago. New battery, engine turns over, Gauges do not activate when key is turned on. Can smell gas while turning over. Pull front spark plug and got spark when I turned it over. Thanks for your help. JST Share this post Link to post Share on other sites
ericj 1,579 #2 Posted February 10, 2015 the dead gauges could be a fuse. if you have spark and smell fuel it might be old fuel the onans can be a bear to start when they sit for a long period of time. might try spraying carb cleaner in the carb and see if you can get it to fire on that good luck eric j Share this post Link to post Share on other sites
Brunner 0 #3 Posted February 10, 2015 Is the choke blade closing inside the carb? I am having the same trouble as you, so I decided to try some starting fluid. It did start on starting fluid, but I noticed that when I tried to use the choke, that the spring was gummed up and the choke blade wasn't closing. I cleaned the spring real good and now the choke works. I am still having trouble getting it started, but I am finding several little things that might be contributing to my problem. I will update my post as I go along and hopefully some of it will help you. Share this post Link to post Share on other sites
ericj 1,579 #4 Posted February 10, 2015 (edited) last summer i traded for a 520. i wanted a 520 for a dedicated snow blower tractor for my 2 stage blower and hopefully ad a cab to it down the road. i was told when i got it that it possibly had a bad trigger on it. my friend that i got it from took as a trade in and hadn't fooled with it. the po had taken it to another dealer and they told the po that it needed a trigger other things and wasn't worth fixing. i thought i was told the coil had been replaced but don't remember for sure. any way i brought it home and cleaned the carb and checked the trigger, it checked out ok so i proceeded to get it fired up and added my 2 stage blower. it ran okay but not great and started harder then i would have liked to have had. i changed the spark plugs out and that helped but didn't correct the hard start especially when cold. when cold you would have to crank and crank on it to get it started. i tried several different things to get it started like spraying carb cleaner in it and nothing helped, finally last sat i tried to start it and almost gave up. i needed to carry a heavy motor out of the back of the shed and the dang thing wouldn't start. ​ i walked away and got another tractor and cart to help hall the motor to my truck and decided to try one more time and luckily it did start. it always would start after the first cold start and it had some stumble when throttling up around mid range rpms. i was so disgusted i was ready to swap motors on it. so i talked to my friend who i got it from and he suggested plug wires and check the coil. i replaced the wires last night and still no start. so i found a used coil that i had laying around and hooked it up and it fired right up. i just went out to the shed and tried it again and it fired right up. so i think i fixed it for now till something else goes lol . so i thought i would share my experience with everyone else and hopefully help somebody else out of a jam since this is my blower tractor i needed to be able to depend on it and i wasn't sure that i could till now. so now i feel a lot better eric j here is something else i found that can cause hard start on the onans. if you check the onan service manual it will tell you how to check your coiland ignition module. it goes through what ever you need to know about the onans step by step eric j Edited February 10, 2015 by ericj Share this post Link to post Share on other sites
jst 0 #5 Posted February 10, 2015 Thanks for the response. Tried starter fluid and it did not start. Checked the choke assembly and it is operating fine. Will check my manual and troubleshoot the coil this afternoon. Thanks again !!!! JST Share this post Link to post Share on other sites
kiotiken 105 #6 Posted February 10, 2015 Jst with key on try wiggling the wire connection that is on top of battery. Watch and see if the gauge lights come on our flicker. That happened to me and I found a bad wire in the connection. Good luck Share this post Link to post Share on other sites
WH nut 553 #7 Posted February 17, 2015 Sounds like its flooded, change spark plugs Share this post Link to post Share on other sites
