I am new to the forum and have spent hours on google.. I am hoping explaining in a paragraph what I know will help someone with more knowledge than me help me. I hope this is the right spot.
My mower is used for home use only. One day it wouldn't start.. Someone recommended I just jump across the posts on the solenoid to see if it started, and it did. I ordered a solenoid and put it on it and it started right up. I thought, "wow that was easy".
Then 4-5 mows later, it stopped working again. Same situation I jumped the posts on the solenoid and it started right up. This time rather than buying a regular $12 solenoid I went to a scag dealer and bought the OEM solenoid for $30 and put it on.. and then it worked again.
2-3 mows later it stopped again.. I can still jump across the posts and start it, but now I'm realizing its not just a solenoid issue.
The current solenoid I am using can be jumped across the posts and work... so I took it off. I put a 12v charge on one side of the prong (ignition) and grounded the other prong. I then ran 12v to the post. When I turn the power on the ground/ignition off, then I do not get 12v across both posts.. when I turn the power on then I do get a solid 12.4v reading. THIS leads me to believe my solenoid is fine and perhaps it has been coincidence that my mower works for a few spins after changing out the solenoid.
I am at a loss... and probably all that I have listed above is useless information because it was done improperly.
I suspect you are having an issue with one of the switches on the direction levers, or the seat switch, or the pto switch that works sometimes and not others.
The switches mentioned above control the 12 V feed to your solenoid and the ground to the solenoid if it has 2 small ( trigger ) posts.
On the early models there are relays on both sides of the solenoid and on the latter models there is a relay on the + side and the "Tiger Eye" control module looks after checking all of the safety switches are functioning properly.
So you can check the safety switches and try replacing the relay ( won't hurt to have a spare )
It is a std 30A headlight/horn relay.
After that it will be the control module which AFAIK only Scag dealers can test.
