I was wondering if anyone has had this problem. I have had 3 hyster s50xm's now all with the mazda engine and spectrum fuel system in them do this. when cranking its like it tried to fire backwards and bucks but once fired it runs great. I have figured out with no fuel in the system it cranks normally (eliminating starter and ring gear). I have even had a known good running truck right next to the bad one and swapped distributor, fuel converter, many other parts with no change and im at a loss. I would like to solve this as one truck does it so bad it eats up starters every few months