Is there a relay? Which one? to operate the starter solenoid.  I replaced my occaisionally cliicking starter for a 2nd hand one which turns out to be lazy and also sometimes clicks. Is the clicking the relay or the solenoid?

It sounds like your solenoid. Check first that the battery is up to scratch, with a voltmeter. What does the voltage across the pos. and neg. drop to when you try to fire the engine?

There is a relay for the starter listed on the Y25DT Auto setup. Not sure if it applies to earlier tractors but yes, the solenoid is powered by a relay in the box by the battery (relay is at the back end of the box, in the corner nearest the passenger side wing).

Manual tractors don't appear to have the relay as they don't have the starter interlock.

Kevin

.. and with respect to your problem, as said, check the battery is 100% and that all wiring between it and the starter is solid with no loose crimps and not getting warm after cranking a few times.

Could be high resistance in the feed to the solenoid so the wiring between it and the relay contacts, the relay, and the feed to and from the ignition switch.

Kevin

Thanks. I bought a new battery, made no difference. I'm thinking it might be carboned contacts in the relay as the click doesn't seem loud enough to be the solenoid.