07-01-2017 12:43 - edited 07-01-2017 04:10
What make, model, and size propeller did you take off?
What make and model propeller did you buy?
The propshaft has a bit of fore and aft normal movement, or are you describing loose propeller movement on the propshaft?
07-02-2017 06:42 - edited 07-02-2017 06:44
The BS prop is an aftermarket design, not an Evinrude product, and it may require a different thrust washer and other hardware. Check with the manufacturer or store where you bought it. We are unable to assist with non-Evinrude products.
Inspect your gearcase carefully for any damage inside the exhaust cavity area and especially to the inner circumference where the prop outer-diameter has to fit closely to seal off exhaust gas leakage when running.