Question about shear/drive pins

[Kengh]

Does the Propeller Nut hold the Drive Pin in? I am talking about a '62 Evinrude.

As in a drive pin will not stay in on its own, it gets covered and held in by the Propeller Nut?

I don't know what was being used as a drive pin before, because it broke off and fell into the water, but it certainly wasn't covered by a propeller nut. It was just put through the holes in the shaft and the holes in the propeller itself. I am so confused

And wouldn't a cotter pin suffice for holding the propeller on?

 

[14ftgrumman]

Re: Question about shear/drive pins

NO. It needs the real drive pin for the application.

The drive pin goes thru the hole in the prop shaft, ropeller gets slid onto the shaft and the indents on the inner part of the prop go over the drive pin, then the prop nut goes on, nut gets snugged up, and backed off until the cotter pin can go thru the nut and shaft to hold the whole thing together.

 

[Kengh]

Re: Question about shear/drive pins

But you see in the picture below where the drive pin gets inserted? That copper colored part extruding from the propeller itself is not part of the shaft, it is part of the propeller and it lines up with the holes on the shaft. Why couldn't a cotter pin go through there to hold it on? im pretty sure that's how it came and it ran until it hit a rock.

 

[Sir Robin]

Re: Question about shear/drive pins

Small motors..... 7 1/2 9.9 15 18 20 25 use the pin and nut as decribed above, The later 35 40 the pin goes through holes in the prop and a hole in driveshaft then a rubber housing that "looks" like a prop nut goes over the pin.
Look up 40 hp Evinrude at brp.com

 

[Sir Robin]

Re: Question about shear/drive pins

Is it a late 60's motor?

 

[Kengh]

Re: Question about shear/drive pins

1962

why not push this through and bend it back?

 

[Craig-]

Re: Question about shear/drive pins

But you see in the picture below where the drive pin gets inserted? That copper colored part extruding from the propeller itself is not part of the shaft, it is part of the propeller and it lines up with the holes on the shaft. Why couldn't a cotter pin go through there to hold it on? im pretty sure that's how it came and it ran until it hit a rock.

Was there a nut on the shaft before and it left when the pin sheared?

 

[Sir Robin]

Re: Question about shear/drive pins

I C..... NOT omc? There is a Pin that goes through the hole as you suspect then a prop nut with a pin cover spins on and holds the pin and a cotter pin holds the nut assembly. Just using a cotter pin will most likely damage or DESTROY the prop shaft. The shear pin is supossed to"SHEAR" with a prop strike, saving the shaft....

 

[Kengh]

Re: Question about shear/drive pins

I ordered the OMC prop nut and thrust washer as well as 5 omc shear pins...they won't be here until later this week. But If I stick a cotter pin through there and DO NOT hit anything, then it will be fine correct, for temporary use of course.

 

[Sir Robin]

Re: Question about shear/drive pins

I won't say it's ok...... though i have done it in a pinch

 

[yorab]

Re: Question about shear/drive pins

Keep in mind that by putting a cotter pin through that hole that is not approximately the same diameter as the hole could result in the edges of the hole getting mucked up a bit. You would then have to clean up that hole before you use the real shear pins that are rated for the shear stresses produced by your motor.

 

[jgriner]

Re: Question about shear/drive pins

shear pins are rated to break at a some pressure (lets say 300 lbs) your cotter pin may break at (10lbs) most likely it wont break jsut bend untill it doesnt hold the prop on, it may wrap its self around the shaft, then the nut walk up and lock over the top of it. or then again it might work....

someone today on this forum said you could use a stainless steel rod cut to size, as a pin.... i would do that before a cotter pin
but then again a stainless steel rod maybe double the sheer streinth of the sheer pin

 

[Chris1956]

Re: Question about shear/drive pins

What are the shear pins made of? Usually brass or stainless. I would use a brass bolt, with the head cut off, and cut to length, until the new shear pins arrive. The Fat-Fiftys used a 5/16" stainless shearpin. The 40HP motor used a brass shearpin, likely 1/4". So try a 1/4"-20 brass bolt.

 

[Sir Robin]

Re: Question about shear/drive pins

hope the real pin & nut got to ya before any real damage was done. By the looks of yer prop, a LOT of stuff has jumped out right where you were going........The shear is calculated by shaft/prop dia, hp and hub bushing, so minimal damage happens from a strike. I HATE busting stuff...........

 

[Sir Robin]

Re: Question about shear/drive pins

The prop will fall off by using just a cotter key if there is a strike. Do you run a shallow river?

 

[F_R]

Re: Question about shear/drive pins

The proper pin for that motor is a 1/4" diameter Stainless Steel DRIVE PIN. It is not a "shear pin", and is not intended to shear. The rubber hub in the propeller is supposed to absorb the shock of hitting rocks and stuff. It sure looks like you hit a few. Although not intended it is possible to shear the stainless drive pin. But you would have to clobber something might hard before that would happen.

A cotter pin would shear off almost immediatly.

The drive pin holds the prop. The nut holds the drive pin. The cotter pin holds the nut.

 

[boobie]

Re: Question about shear/drive pins

Geeez. I can remember years ago when all shear pins were made out of brass. Everybody always carried extras with them along with cotter pins and a pair "duck bill" pliers. Seemed we didn't have so much gear damage or prop damage in those days. And then along came the stainless steel pins, "slip hubs" and splined shafts.

 

[ezeke]

Re: Question about shear/drive pins

A lot of us are as old as these motors and have no problem remembering that they all had the rubber bushings and the stainless drive pins.

 

[boobie]

Re: Question about shear/drive pins

Do you remember before stainless steel drive pins and slip hubs ? I do. The only thing you could buy at any marina was small packs of brass shear pins and cotter pins.

 

[CatfishMN]

Re: Question about shear/drive pins

But these are not shear pins, right? These are drive pins, and should not break. The prop hub is the safety device, right?

My 1972 Johnson 25 is the same way, yeah?