RjCorazza
Elite Member
I have had this problem on several tractors (especially older John Deeres). There seems to be to much voltage drop on the small wires in the loop to the starter solenoid. From where ever the ignition switch is getting it's power through the switch contacts then through the various safety contact switches then to the starter solenoid. There isn't enough voltage/power to pull the starter solenoid completely and engage the starter motor gear and make contact with the heavy duty switch at the back of the solenoid which connects the battery to the actual starter motor.
To remedy this put a small 40amp relay right at the starter "https://www.amazon.com/PACK-AMP-Wat...lja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1"
All the key switch has to do is pull this small relay which will power the starter solenoid. See attached diagram. What you want to do is remove the small trigger wire from the solenoid and connect it to pin #86(white wire). Ground pin #85(black) to block. Wire pin #87(blue) to small terminal of solenoid where you removed the key switch wire. Run a wire from the large battery terminal to pin # 30(red). Now when the key switch actuates the low power relay the solenoid is going to get full 12 volt power. Hope this is making sense and good luck.
This is what I did for my Kubota ZD mowers that had starter solenoid activation problems. Worked great!
You can find pre wired kits, or put it together yourself for very little $$$.