No Starting

8N with front mount coil starts well enough when cold and runs beautifully with lots of power, never misses. But after turning off a hot engine and trying to restart soon after, starter will crank engine without firing. (Throttle set a quarter open, no choke) After waiting hours for cooling off, tractor again starts. All wiring is original, including resistor, battery is 6V. Any ideas?

While it could be a compression issue, start by checking the most likely problem: spark.


Next time it won't start, check quickly for spark. When I say quickly, I mean get off the seat, grab the tools & do it right then. Do not wait a minute or two.

First, turn the key on, crank the engine & look at the ammeter. What is the needle doing? Does it show a constant discharge, no movement at all, or does it move back & forth slightly? Next, hook up your spark checker*, turn the key on & crank the engine. If the spark jumps the 1/4” gap, you probably don’t have a spark problem. If it won’t jump the ¼” gap, you have a spark problem. If the ammeter needle shows a constant discharge, or doesn’t move at all, that also tells you that you have a spark problem. Jump the ignition switch w/ a jumper wire & see what happens. If it runs, you found the problem. If it doesn’t have spark after you jump the ignition switch, post back for more info on further troubleshooting. (and do not forget to turn the ignition switch off; see tip # 38


There are ways to check for spark that work & ways that don't. Some folks think that checking for spark means pulling a plug wire off & looking for one. Well, it's the distance the spark jumps at the plug that gives you the info you want. It takes about 17kv to jump a 3/16" gap & 22kv to jump ¼” in the open air. Remember, it’s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air creates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running. A store bought plug checker (in the picture) will work better than an old plug because it won’t shock the snot out of you like an old plug might!

Post back with results or more questions.



*If you don’t own a spark checker w/ an adjustable gap, buy one. In the meantime, an old spark plug w/ the gap opened to at least ¼” will work. Ground it to a rust & paint free spot on the engine turn the key on & look for a spark.
75 Tips

Coil on it way out can cause that. Time to check and compare spark. Check the spark at a couple of the plugs before you start it the first time then compare the spark when hot. Spark should be a nice blue/white and jump a 1/4 inch gap or more.
If spark is still good slowly remove the gas cap and see if with it off it will start the tank vent could be clogged up

on hot crank with no start.. yep.. check spark first..

Corroded old ignition switch can also mess you up.