Shear pin alternative?

[X80057X]

Hey y'all. I looked to post this in the technical section someone told me about but wasn't able to locate it. Guess I'm a knucklehead. I'm wondering thoughts of a nylon screw alternative to what looks like a brass shear pin. My local marina no longer stocks various size pins and are out of what I need. The motor is a 7.5 hp 2 stroke. This motor has since been discontinued from the manufacturer along with a majority of the parts. I've sourced an online dealer but $4 for 2 pins + what will be roughly $7 shipping seems a bit excessive. I sourced a nylon screw at my local hardware store for $0.36 which seems durable enough to spin the prop yet is soft enough to snap in my hands, I snapped one. Opinions? Thank you

 

[jestor68]

Re: Shear pin alternative?

A piece of plastic will not be strong enough. Buy the proper shear pins while you can.

 

[gm280]

Re: Shear pin alternative?

If that is going on your 2 cycle outboard, forget it. The nylon screw is too easily to snap as you have already found out. I'd either buy a few (to have extras) or look for a brass rod of the correct diameter and cut your own... But seriously nylon will probably break just revving up your outboard out of the water unloaded. Once you load that prop in the water, that nylon screw will be toast real quick...

 

[Bondo]

Re: Shear pin alternative?

Hey y'all. I looked to post this in the technical section someone told me about but wasn't able to locate it. Guess I'm a knucklehead. I'm wondering thoughts of a nylon screw alternative to what looks like a brass shear pin. My local marina no longer stocks various size pins and are out of what I need. The motor is a 7.5 hp 2 stroke. This motor has since been discontinued from the manufacturer along with a majority of the parts. I've sourced an online dealer but $4 for 2 pins + what will be roughly $7 shipping seems a bit excessive. I sourced a nylon screw at my local hardware store for $0.36 which seems durable enough to spin the prop yet is soft enough to snap in my hands, I snapped one. Opinions? Thank you

Ayuh,.... An ole bend nail would work Better....

If you can snap it in yer hands, it won't last an Instant as a shear pin....

 

[X80057X]

Re: Shear pin alternative?

That all seems fairly conclusive with my buddy I talked to as well. Hmm. So are shear pins generally fabricated out of brass? Cause the hardware store does stock brass rod I could certainly cut my own from. Is it really just that easy?

Although very mechanically inclined, this is my first outboard AND 2 stroke. I've trouble shot the crap out of a no start issue leading to it running rich, then lean. I completely rebuilt the carb along with servicing the gear lube and replacing the impeller and pump housing. I knew nothing about a shear pin until pulling ashore by means of the trolling motor where an old timer suggested what the "no go" problem was. I thought the maiden voyage was the first and last. I was pretty bummed till he gave me hope!

 

[Howard Sterndrive]

Re: Shear pin alternative?

get the right shear pin - buying local is great, but there's a point where you have to order the right stuff online sometimes
$11 is peanuts when you're paddling into the wind

 

[steelespike]

Re: Shear pin alternative?

A brass pin of the right size will work fine.

 

[jwalterus]

Re: Shear pin alternative?

I've always used grade 1/4" grade 2/3 bolts for shear pins in my snowblower augers
hard enough to hold up, but they shear off easy enough when they hit an obstruction
try it at your own risk, does it function like it should in my snowblower? yes, would I use one in MY outboard? no
most hardware stores (menards, ace, etc) have a rack of various sized shear pins, you could see if they have one that would work

 

[Texasmark]

Re: Shear pin alternative?

+1 on the nail. When it gets rusty get another.

Mark

 

[X80057X]

Re: Shear pin alternative?

I may still try the nylon screw just for sh*ts and giggles But I think I'm going to get some brass rod and cut my own. Seems fairly conclusive this is an acceptable alternative. A couple people in a status on facebook chimed in to say it'd work, one in particular who's a legit friend said that's exactly what he does. If I do in fact try the nylon I will report back in this thread as to my results. Thanks y'all for input and suggestions

 

[X80057X]

Re: Shear pin alternative?

And I haven't yet checked home depot or lowes but my local true value only has snowblower pins, which are more like bolts. Not suitable for my little 7.5 hp outboard.

 

[Texasmark]

Re: Shear pin alternative?

I'm going to say that with a rubber slip hub prop that pin is more of a "drive pin" than a "shear pin" on a 7 1/2. As small as those cubes are, if you hit something that the rubber hub can't handle it will just kill the engine. Besides the rubber will cushion the impact to the engine mechanics even if it does die. Should start right back up.

On a little 7 1/2 you aren't going all that fast so things have time to happen. If you hit anything but the prop the engine will raise up over the obstacle and settle back down with nothing hurt and the engine will still be running. Dinging up a blade on an engine of that size is remote to say the least....unless you are running a river bed.

Mark

 

[X80057X]

Re: Shear pin alternative?

Thanks for your input. Although as I said, a piece of waterlogged driftwood lodged itself in my prop leaving me propulsion-less....later determining the shear pin broke. Also, on the manufacturer website and viewing the diagram for my motor, the name of the object in question is in fact "pin shear." You were correct in one aspect of my situation, the motor did start back up....just didn't go anywhere.

 

[X80057X]

Re: Shear pin alternative?

Without the proper size rod available, I went with a brass screw. I simply cut off the head and viola! $0.46 replacement. Done.

 

[kfa4303]

Re: Shear pin alternative?

Glad you got it fixed. ACE hardware also sells brass rod in various diameters. I bought a 6' length which is enough to make dozens of shear pins.

 

[X80057X]

Re: Shear pin alternative?

Obviously pitch doesn't matter but I went with an 8-24 screw. An 8-32 woulda worked just as well. My buddy actually just picked up a 7.5 Ted Williams. His has a holster under the hood for spare shear pins. Tecumseh apparently decided to upgrade the pin shaft diameter cause his are thicker where a 3/16 rod would work...but is larger in diameter than mine. But the "8" size screw works perfectly in mine.

 

[Texasmark]

Re: Shear pin alternative?

Obviously pitch doesn't matter but I went with an 8-24 screw. An 8-32 woulda worked just as well. My buddy actually just picked up a 7.5 Ted Williams. His has a holster under the hood for spare shear pins. Tecumseh apparently decided to upgrade the pin shaft diameter cause his are thicker where a 3/16 rod would work...but is larger in diameter than mine. But the "8" size screw works perfectly in mine.

Dad had a 10 hp Scott Attwater, about a 1955 version, gold top and green the rest of the way down. On the steering arm root, was a litle rubber grommet in which 2 shear pins and 2 cotter pins were made available for use as necessary. Convenient.

Glad you got creative and "got-r-fixed".

Mark

 

[airshot]

Re: Shear pin alternative?

In my small outboard days when money was tight, I also used brass screws, on some ocassions I used a piece of aluminium rod, that worked fine as well. Once you get into bigger motors then a proper shear pin will last much longer.

Airshot

 

[X80057X]

Re: Shear pin alternative?

In my small outboard days when money was tight, I also used brass screws, on some ocassions I used a piece of aluminium rod, that worked fine as well. Once you get into bigger motors then a proper shear pin will last much longer.

Airshot

I know I'm not unique in this world, glad to hear this has been done before as much as my mind says it'll be fine it's nice to know it will be. But now my question is, to you, did you ever have an incident to put the brass screw shear pin to te test?

Maybe someday I'll have bigger boat and motor but for now, what I have serves it's purpose just fine