shear pin issues

[Texasmark]

Re: shear pin issues

what is the diffrence between a drive pin and shear pin? Mine is like the one pictured.

The pin that goes through the prop shaft after the prop is installed is actually a drive pin.....it connects the prop to the drive shaft so that it can be driven.

Just so happens it breaks (shears) when some hard objects are struck, hence the jargon term "shear pin".
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In reading the replies I had a couple of thoughts. It is possible that the brass insert in the rubber hub has wallowed out and this could allow for some slack that is undesirable.

Next, it is possible that the rubber "slip hub" no longer slips when obstructions are struck, hence the shear pin takes the whole load.

Since the prop is dinged up already, the correct OEM pin and a new prop may solve the problem.

My 2c,

Mark

 

[Home Cookin']

Re: shear pin issues

I'm wondering if your nose cap is too short, so you can't screw it down, so the pin beats up the slot in the prop--that and you have brass pins (I still have a few of my dad's).

I'm not sure; I might have yor OMC manual on a PDF. Or paper. finding it will be the trick.
I found manuals at our public library.

 

[kbait]

Re: shear pin issues

If your prop hub isn't worn like the photo in the service bulletin, just tighten prop nut to next hole, as per bulletin. W/stainless drive pin, you should be golden.

 

[shootindave]

Re: shear pin issues

Ok guys..... this is one of the best forums I have seen on the net...... and due to my expensive gun/hunting habits I belong to A FEW.

Thanks a bunch.

I believe my problem was two fold.........

#1 the shear pins provided to me with the boat were brass...... and God knows what size. The correct ones are stainless steel.

#2 I did not know I needed to take a wrench and tighten the nut onto the prop to line up the holes for the cotter pin...... I did as the previous owners showed me...... back it out untill the holes line up.

I went to a very helpfull local boat shop and they cleared everything up for me. I now have 5 extra shear pins and 2 extra cotter pins in the boat.

After using a random screw for 3 miles as a shear pin.... i figure overkill is OK in the future.

- Dave

 

[HybridMX6]

Re: shear pin issues

After using a random screw for 3 miles as a shear pin.... i figure overkill is OK in the future.

- Dave

I used to have a 1971 20hp that had a similar style drive pin, and I always carried spares and spare cotter pins as well. Never hurts to be safe, and it's not like they are huge and take up a lot of room or anything. My prop was a bit distorted around the drive pin area, so it would occasionally break them, so I carried spares all the time. I eventually bought a spare prop and used it instead of the old one, and kept the old one as the spare. Great motor, never let me down.