Will a cotter pin work as a shear pin?

fishermanms

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I sheared a pin today when I bumped a stump with my lil 6hp Johnson. Was ust wondering if I could use a cotter pin as a substitute for a day or two till I get some new ones....Or anthing else that might work. Thanks for any advice...Fishermanms
 

Townsie 51

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Re: Will a cotter pin work as a shear pin?

Might work for a short time. Anything is worth a try in a pinch. I have even used a nail when I could not find anything else. Wount take a lot of torque, but goy me home.
 

kmk_7110

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Re: Will a cotter pin work as a shear pin?

I wouldn't recommend it, especially if your going to use it in the same water. You may hit that stump again or another one if not fimiliar with the waters, and screw something else up, or break something and be stranded.
 

Willyclay

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Re: Will a cotter pin work as a shear pin?

Yes, if you take it real easy. I have a friend who sheared a pin and only had match sticks to replace it with. He made it back to the dock, it just took a while!
 

fishermanms

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Re: Will a cotter pin work as a shear pin?

Yea... Whatever I do Ill take extra precautions..I could fabricate one if I new what they are made of. I thought about making one out of brass. I checked the local auto zone and O'reallys but they did not even know what they were...Can you believe that!
 

tashasdaddy

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Re: Will a cotter pin work as a shear pin?

just make sure it is temporary. you don't want it to rust into place, and not be able to get it out.
 

bgbass.1

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Re: Will a cotter pin work as a shear pin?

cotter pins are made from brass if you have some the same diameter you can make them yourself been doing it for years with no problem.
 

tmcalavy

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Re: Will a cotter pin work as a shear pin?

Yeah it might get you back to the dock...cotter pin. Buy some brass rod the right diameter at the local big box store and cut your own.
 

F_R

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Re: Will a cotter pin work as a shear pin?

What year is your 6hp? Many of them use a part number 307949 DRIVE pin. It is 3/16" diameter by 1 3/8" long and is made of Stainless Steel. It is called a drive pin because it is not supposed to shear. The rubber hub in the propeller takes care of the impact of stumps and bumps.
 

ezeke

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Re: Will a cotter pin work as a shear pin?

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Silvertip

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Re: Will a cotter pin work as a shear pin?

Buy a small package package of bronze brazing (welding) rods of the proper diameter. You can cut as many as you want for a couple of bucks.
 

DHPMARINE

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Re: Will a cotter pin work as a shear pin?

I missed the post that asked where your spare (reserve) pin was.

Guess you'll have one next time.

Anything will work,but get the real thing.

DHP
 

12-ft-skiff

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Re: Will a cotter pin work as a shear pin?

I will personally guarantee that a 307949 is a shear pin. It is precisely what I use in all six of my 9.5HP motors, and the kids manage to shear at least one a year. They usually break them by trying to shift at too high RPM.

I have a '69 Johnson 9.5 - is that the shear pin for my motor as well? I just got the motor, and after reading this, I think I should probably pick up a spare.

EDIT: Nevermind, I found the BRP Part Catalog and verified it's the same number. Thanks!!
 

JB

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Re: Will a cotter pin work as a shear pin?

Please do not "make" substitute shear pins. The OEM pin is made of an alloy selected to protect your prop and geartrain. The real thing is too easy to find and too inexpensive to mess about with substitutes that may result in a destroyed geartrain.

1. Always carry at least one spare. Many engines had a clip inside the cowling specifically for carrying a spare shear pin.

2. In an emergency you can reuse the sheared pin. Here's how.

When the pin shears it breaks into three pieces; one long and two short. The long one is inside the propshaft. Switch places between the long one and one of the short ones. That will give you half a shear pin which should get you back to the dock. Did that a few times when I had already used the spare in rocky, unfamiliar waters.
 

F_R

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Re: Will a cotter pin work as a shear pin?

I did not intend to imply that the drive pin won't break if you really clobber it. It is a drive pin and is so called in the book. Reminds me of the time I sold a guy a new 2hp. He asked about the shear pin and I told him there was a spare in the owner's manual kit. But also told him it is a drive pin not intended to break unless really abused. Well a few weks later he was back and upset because I told him that he "didn't need a spare". (That's not what I said at all). Seems he took the motor up north somewhere and put it on a canoe and went way out in the wilderness and shot a moose. Loaded the moose in the canoe and headed for home, only to hit a rock and broke the drive pin. Seems he didn't take the spare along because I said he "didn't need it". How 'ya going to fight stupidity?
 

fishermanms

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Re: Will a cotter pin work as a shear pin?

Well... Some mighty good advice here. In the meantime, I made a perfect fit from a grade 8 bolt. And have installed it. BUT... today is Sunday and its hot and humid and no wind. And I caught plenty of fish yesterday. I have decided not to take her out today, stay here and cook fish this evening. This lake I was in yesterday is a 600 acre impoundment located about 10 miles from my home on the Noxubee National Wildlife refuge. Every year in August they pull the lake down low...real low, to kill off the duck weed and lilly pads. Then all the creeks that were dammed up to form the lake emerge as well as all the thousands of cypress stumps. Then fishing thru fall is really something else. Thats how my prop found the stump yesterday. But I was going slow, (the entire lake is restricted to a no wake zone). The pin did break in three places as Ezeke said it would. I went online to Crowley marine and their diagram does idenify the part as a "drive pin" as FR said it is. But I dont believe stainless steel would have broke in three places. No offense FR, if the original was stainless it has probally been replaced by something that is breakable under mild to moderate stress. FR my motor is a 1974 Johnson 6hp model 6R74-C. JB thats a pretty slick way (swapping the long for a short) to get by in a pinch. I am very picky with this motor. I just spent a bundle on it, my trailer and boat and hours and hours of hard hot work. And you all were here to help me out a lot and spent your time and effort as well. I have made a mistake making this pin outa grade 8 steel...But I am going to remove it and search the area and local marine shops for a replacement and several of them as spares. Thank Ya'll all for your suport...I appreciate all of your help... Fishermanms:)
 

ezeke

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Re: Will a cotter pin work as a shear pin?

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moterboat

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Re: Will a cotter pin work as a shear pin?

sounds like if you start useing different metals for A shear pin,then you may take a chance of ethier damaging your lower unit due to too hard of a pin,or you may end up paddeling due to shearing a pin that is too soft. they call them shear pins for a reason,thats to protect your lower unit.;)
 

F_R

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Re: Will a cotter pin work as a shear pin?

I beg to differ. A 1974 6hp Johnson DOES have a rubber shock hub in the propeller to protect the drive train, and it does take a 307949 stainless steel drive pin. Go ahead and use a soft "shear" pin if it makes you happy to be changing it every time you touch something underwater, or just wear it out by shifting gears.
 

fishermanms

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Re: Will a cotter pin work as a shear pin?

FR and Ezeke,

OK, Everybody does agree on the part number and I do know it is called a drive pin. Now what it is made of....remains to be seen. However... I am ordering the part number everybody agrees on... Also I have two different websites below to go to and look at the diagram's and you will see that there is no mention of a grommel anywhere in the gear case or propeller. There is one higher up the leg on the water tude. But whatever it is made of, alloy, metal, stainless steel or whatever...It will be installed on my Johnson. So check it out:
crowleymarine.com/brp_parts/diagrams/32561.cfm

Fishermanms
 
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