What does a 2005 Yamaha F25 use instead of a Shear Pin?

[yakoun]

I got in a situation on the weekend where I found myself running up a fairly skinny river between two lakes with my 15' Smokercraft Alaskan with a 2005 Yamaha 4 stroke F25. Everything turned out OK and I didn't hit anything. But it got me doing some research when I got home about how to better equip myself for situations like that. Aside from unlocking the trim lock (manual trim) and possibly equipping the leg with a river runner, I would like to be equipped with a spare prop, a prop wrench and whatever newer motors use instead of a shear pin. Has this concept been replaced with something else? Looking at the diagram in the service manual I have I see what is called a "collar" that seems to go between the splines on the propshaft and the hub of the prop - does that perform the same function as a shear pin used to - meaning if I hit a rock with the prop and the prop stops spinning, what prevents damage to the lower end? Appreciate any intel on this!

 

[flyingscott]

There is no shear pin in that motor has splines on the propshaft that match the hub in the propeller. Two different kinds of hubs in propellers today. One is rubber its pressed in to the prop need a prop shop to fix. When the rubber hubbed prop hits something the hub will absorb the impact or break loose it will usually reconnect to limp home. The other style is plastic it is removable and will usually absorb an impact or break pretty much the same as rubber. This has the advantage of just being able to replace the hub if there is not a lot of prop damage. Either way always carry a spare prop you don't drive your car without a spare tire do you. Which hub you get will depend on manufacturer.

 

[yakoun]

flyingscott, thanks for your clear, concise explanation! The "breakaway" component is now contained in the hub of the prop itself - whether the hub is easily replaceable or not. I have a spare prop, the pressed hub style - I'll make sure I carry it along with a prop wrench from now on.

 

[robert graham]

There is a prop called a Comprop that's made of a black plastic composite material and made to break if you have a prop strike....they're fairly inexpensive($80) for some models....but they're a lot cheaper than new lower unit gears.....seems they'd be good for your application.