I have searched the forum and have found several posts about similar issues, but none that are exactly the same as mine. M6800 4x4 with cab and loader. When starting the tractor the tractor will start when the key is in the start position and die when the key is returned to run. It will do this 4 or 5 times. after 4 or 5 times of this the tractor will start and run fine, until you shut it off and then the process starts over again. If i hold they key in start during this it will continue to run but die when key is returned to run. no amount of fiddling with the key or throttle input changes the process, it always takes 4 or 5 times maybe 2 or 3 occasionally after the tractor run for a while. i have checked and the vents are not clogged, changed fuel filter, previous owner replaced shut off solenoid a while back but that didn't fix it (not opposed to buying another to try). tractor has been like this for a good while and i cant seem to figure it out.