onan 19.5hp spark help

[gwt 0]

hi guys, i,ve got a 19.5 onan with a spark problem, when i crank it over with the plug out the only time it sparks is when i just let off on the key switch, i can crank it for a short or long period of time and see no spark until i just let off the key switch then i see just a quick spark. any ideas? thanks

[UCD 14]

Bad ign switch.

[D-17_Dave 12]

Welcome to the club George. And Maynards correct. You have a bad ignition switch. These switchs are designed specificly for the tractor on the powermax sized tractors so best to secure one from a Simplicity dealer.

[Bunky 3]

Welcome to the club.. I have to agree with UCD sounds like the key switch is Bad.....

[gwt 0]

thanks guys thats what i thought, but it always helps to get a second opinion seeing i'm new to the onans, (allis 620) thanks again i'm sure i'm going to have alot more questions in the future (haha) gwt.

[tec2484 1]

Welcome to the club George!

[Killer_A-C 0]

Welcome also to the club. Best $10 you will ever spend,Matt

[Al 6]

Hi, I would check to see that there is 12 volts to the coil when the switch is on and in start. Next I would check with a little test light to see if the light blinks on and off when the engine is cranking. A shorted condensor can cause this, as can anything that gronds out the insulated point contact. For example a bare wire from the coil to the points touching ground. The points break and the shorted condensor is just like having a jumper across the points. When you shut the switch off, it has the same effect as opening the points. This will tell you if the switch is working properly. Al Eden

[gwt 0]

Ok Al i checked the voltage, i have 12v at the coil, and about 7.4v while cranking at the coil. this all started when it shorted out because of a bad pos coil wire, everything died, i think i even blew out the rectifier, but now i just need to get spark again. let me know what you guys think, and thanks i,m happy to be in the club.

[gwt 0]

oh yes, i did try a test light while cranking and it did blink but the bulb gets real dim while doing it. i dont know if thats normal or not?

[UCD 14]

power Max ignition Switch test

[gwt 0]

Ok well I checked the starter switch, nothing in the off position, in the on position I got what the article says to get, batt-ign-acc, but after doing a few times throughout the evening i suddenly got the acc to the start terminal to show huge ohms. then in the start position i got the acc to ground terminals to show 2.9 to 3.0 ohms. plus when in the on position i touch the batt terminal of the ign switch and the positive coil terminal and their is current, but when i turn the switch to the start position the current goes out from the batt terminal of the ign switch to the positive terminal of the coil is that normal? (electrical is deffinetly not my strong point)Thanks again for all the help gwt.

[Al 6]

George, If you are getting the blinking test light at the points and 12v at the coil, I would suspect the condensor but if this has the carbon conductor plug wires, I would substitute a wire off something else. and see if you get spark. I have seen these wires with sections of the conductor 1/2 inch long burned out at the end where they push on the spike terminal at the coil. If they have been moved and handled a bunch could be damaged. I believe that they should measure about 5 to 10k ohms. Next I would try cond. The 7.4 volts is probably within a half a volt of where the battery drops to if it has been cranked quite a bit. If the cond don't fix it, there is a good chance it is the coil. Condensor more likely. If you have a condensor off anything, put it from the points terminal of the coil to ground. If this gets spark, get a new correct condensor. Good luck, Al Eden