I am new at working on outboards, so please bear in mind that these questions may sound basic knowledge to some. I am trying to figure out how the propellor on the force engines are attached. Is there suppose to be prop washers to keep it from touching the lower unit? If so how many? Is there just a lock nut on the shaft or a lock nut with a cotter pin. This motor has been worked on by someone who wasn't mechanically inclined, but I feel there is nothing stopping it from backing out from the shaft. I noticed the flywheel only has a lock nut as well. Is this standard? 