What is a hub on a boat motor?

-My 15hp outboard moves at slower speeds, but when you throttle up it doesnt move. Boat shop said it could be the hub????in your case, its probably just rubber in between the part of the prop that mates with the shaft and the prop itself.

some models, like mercury with its larger props, have a square plastic hub that goes inside the prop. its not unheard of for them to break with no sign of the prop hitting anything. those take about 5 minutes to replace and cost about $30.





BTW, i'd suggest a spare prop, kept in either the boat or tow vehicle, and a spare hub if its quickly changeable.

if you have a spare prop, a minor accident or a tired prop that just fails (should of been taken to a prop shop already) doesnt end the day. its like having a spare tire for your car.
The thing the prop goes onto. They can slip when they're stripped.