prop shear pin

jasperpso

Seaman Apprentice
Joined
Jun 30, 2003
Messages
42
i was taking the prop of my new(to me) boat yesterday, and found that there was no shear pin in it. I know i need one, i am going to pick a couple up next time at the boat shop, but my question probably sounds stupid, how come the prop worked fine? it is a splined shaft prop, so i understand why it is turning, but if the prop turns without a pin, how does it save your lower end when hitting obstacles? i am just confused, i know someone will have a good answer, please straighten my mind out. thanks<br /><br />jason
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,750
Re: prop shear pin

Please post year make and model of your motor. Some (most newer) don't use shear pins. They use a rubber bushing between the prop hub and prop housing. It is supposed to slip if you hit something. These can be replaced at a prop shop a whole lot cheaper than either a lower unit or a prop.
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: prop shear pin

Your Force L/U has both a shear pin and a rubber-hubbed prop.<br />The reason it has been werking is because the shaft IS splined. However, if the pin is missing, by all means, replace it. You can loose your prop, strip the teeth of the shaft splines, and/or wipe-out the prop seal and bearing carrier.<br /><br />The prop hub is what really protects this L/U and prop, not the pin. It's purpose (on your l/u anyhow), is to hold the prop in a certain position on the prop shaft,away from the bearing carrier, and off the prop nut threads.<br />If it aint a Force, Chrysler, I dnno.
 

jasperpso

Seaman Apprentice
Joined
Jun 30, 2003
Messages
42
Re: prop shear pin

yes, is a 86 force/chrysler 50 hp, sorry, i thought i had mentioned that. and holding it one place is a very good reason.. it was about the only thing i was sure it would do. possibly giving the driveshaft a bit more brawn to hold the props center and let the prop blades spin or come off in the event of obstruction? instead of breaking teeth of the spline. i am just assuming that is how it works after pondering your reply?
 
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