F25ESH Starting motor

[onebarefootguy]

I have a 2005 F25ESH 4 stroke Yamaha. I need to replace the starting motor gear assembly and pinion stopper set. What is the best way to secure the armature shaft to keep it from turning when removing the nut that holds these two assemblies on the shaft.

Any thoughts would be greatly appreciated.

[boats.net]

The best way is to use an impact wrench.