John Deere 4100 glow plug pre-heating

[JFahey]

I bought a model 4100 deere that is pretty hard to start. I am not sure how to preheat the glow plugs on this tractor. I tried pushing in on the key but it will not budge. Cranks for about 15 or 20 seconds in 60-70 degree weather before it fires up and smokes like crazy for a little bit. After it has been running it fires right up. Any help is greatly appreciated.

 

[jd110]

The glow plugs work automatically on the 4100 if working properly. When the key is turned to the on position, pause for 3 seconds before cranking. The glow pug module turns off glow plugs after 3 seconds. Glow plugs also are heating during cranking. You can "trick" the glow plugs to heat longer by putting range lever in gear so engine will not crank. Then turn key to crank position for 15 - 20 seconds before placing gearshift in neutral and cranking normally. If this does not help, then chances are good the glowplugs are not working. The relay may be bad, or glow plugs themselves may be no good.