No it doesn`t,but well worth the extra effort.I believe the max gap between impellar OD and the wear ring ID is .040 [use a feeler gage].Can be done while pump is still on boat.Do this, Climb under boat to pump inlet and use feeler gage,sticking it in gap.Its part of the inspection,no need to replace parts that don`t need it.Does the boat rev high while slow to accel.?Is this a twin engine or a single?