We actually had the opposite with our 1550’s. We had two of them and we couldn’t keep them running. Both machines had the hydro pumps replaced, always threw fuel rail codes and would shut down, attachment plates cracked and too top it off our dealer sucks. When the dealer came out, they would blame the motor problems on Yammar, I would take it to Yammar and they would blame it on Ditch Witch. I could never get either one to take blame, I just got rid of both at that point.
Hope yours are better.