You will have to get into the gearbox. It isn't too hard but is time consuming. Sounds like the drive for the tiller has broken. Could just be the chain in the gearbox for the tiller drive.
I too had one that would pop out of gear while tilling. You could hold the lever in but that would eventually bend the shifting fork in the transmission and it would then jump out of the groove in the shifting sleeve. I put new pins on the shifting fork and reinforced it so that it would not bend so easily. It worked fine for a few minutes and then jumped out of gear again. A friend led me to the real solution. The shifting fork is not supposed to hold the shifting sleeve in gear. It is only supposed to slide the shifting mechanism and the detent spring and ball are supposed to do the holding work. I once again repaired the shifting fork but this time ordered a new detent spring part number 932-0863 and a new detent ball part number 741-0862. They cost $4.40 and that was the solution to the problem. I would also order a new shifting fork if yours has been bent. The new ones are a different design that has more reinforcement. It is a lot of work to tear into these so buy the new parts the first time. I was getting adept at the process after doing it three times.I too had one that would pop out of gear while tilling. You could hold the lever in but that would eventually bend the shifting fork in the transmission and it would then jump out of the groove in the shifting sleeve. I put new pins on the shifting fork and reinforced it so that it would not bend so easily. It worked fine for a few minutes and then jumped out of gear again. A friend led me to the real solution. The shifting fork is not supposed to hold the shifting sleeve in gear. It is only supposed to slide the shifting mechanism and the detent spring and ball are supposed to do the holding work. I once again repaired the shifting fork but this time ordered a new detent spring part number 932-0863 and a new detent ball part number 741-0862. They cost $4.40 and that was the solution to the problem. I would also order a new shifting fork if yours has been bent. The new ones are a different design that has more reinforcement. It is a lot of work to tear into these so buy the new parts the first time. I was getting adept at the process after doing it three times.
Answers & Comments
You will have to get into the gearbox. It isn't too hard but is time consuming. Sounds like the drive for the tiller has broken. Could just be the chain in the gearbox for the tiller drive.
I too had one that would pop out of gear while tilling. You could hold the lever in but that would eventually bend the shifting fork in the transmission and it would then jump out of the groove in the shifting sleeve. I put new pins on the shifting fork and reinforced it so that it would not bend so easily. It worked fine for a few minutes and then jumped out of gear again. A friend led me to the real solution. The shifting fork is not supposed to hold the shifting sleeve in gear. It is only supposed to slide the shifting mechanism and the detent spring and ball are supposed to do the holding work. I once again repaired the shifting fork but this time ordered a new detent spring part number 932-0863 and a new detent ball part number 741-0862. They cost $4.40 and that was the solution to the problem. I would also order a new shifting fork if yours has been bent. The new ones are a different design that has more reinforcement. It is a lot of work to tear into these so buy the new parts the first time. I was getting adept at the process after doing it three times.