Small Engines (Lawn Mowers, etc.): 1972 John Deere 110 shuts off when key is released

Question

'72 JD 110  

'72 JD 110   Hey there Eric,
I have a 72 JD 110 with a Kohler K181S 8hp engine.
Last season it ran great until I shattered the piston connecting rod. We just recently replaced the piston and connecting rod, put engine back in and took me a bit to get her to fire up. Finally she did but as soon as does she dies when I release (gently) the ignition key. If I hold key to start she will and roars like a champ getting the engine hot but as soon as I ease off the key it dies :/
Any suggestions? Thanks

Answer
Something is grounding the coil or the coil voltage is only present when the key is in the start position.  

Did you get the coil connections properly connected?  

Use a volt meter to measure the power on the coil.  With the key in the run position the coil should be receiving the positive voltage.

Did you check the power at the coil?

Eric