318 deere won't start

[PaulD]

I have a 318 John Deere that has no spark while cranking. It will spark once when you initially crank it, and once when you stop cranking. Any info will be appreciated. Thanks Paul
 

[El Toro]

I would check the battery cells using a hydrometer. The specific gravity in each cell should read 1.280. If the readings are low you may not have enough battery voltage for the ignition. If any cell has a reading of 1.100
you need a new battery. I use a full size car battery in my Wards garden tractor. I just replaced it because it was 10 or 11 years old.
Hal
 

[R Fink sr]

You have a bad coil just went through that. You can still get from JD.
 

[Ken Combs]

Check for 12v to the +side of the coil when cranking. You may have a bad switch that is not providing that.

Also, it would help to know if you're dealing with a P or B series Onan. Ignition is totally different. and JD used both in the 318 in various years.
 

[geoff gwisdala]

if you have a B series engine, check the points and condensor
 

[PaulD]

The tractor has a late series engine with electric ignition. The key switch is brand new from Deere, it also has a new coil and the battery is in good shape.
 

[El Toro]

If you have points make sure they're open then with your ignition switch in the on position use a volt meter or test lite to see if your have battery voltage on both small terminals. Also rub the points with some 320 wet or dry until they're shiny. Also make sure your points are set correctly & opening and closing and your rubbing block on your points isn't worn off. Hal
 

[Ken Combs]

The test procedure for the electronic trigger is available on the net in several places. I think you just attach a voltmeter to the coil and ground,then crank the engine by hand. The reading should be 12v or so but drop to about 1 volt when the trigger/spark event occurs.

If the trigger is bad, you have to remove the engine to get the flywheel off as the trigger is hidden back there.