I have a 1985 John Deere 850 powered by a Yanmar 3 cylinder diesel engine. I have been having problems starting the tractor. At times when turning the ingition to the start position the starter will not engage but the solenoid will click. The tractor will eventually start but only after many turns of the key. I have replaced the starter, cleaned and/or replaced the battery cable terminals, and replaced the battery. Has anyone else had this problem and if so, what did you do to solve the problem?