Shear pins for outboard - DIY ?

Kingfisher 3 said:
I thought I'd check in advance of any problems and maybe order a spare only to find that my 4hp Yamaha hasn't got one ... some sort of rubber device instead.
Click to expand...

I think it will depend upon exact model. 4 or 2 stroke and the year. I'd start by looking to see if there is a drive pin or a splined drive plus the owners manual should tell you how to replace a shear pin.
 
Kingfisher 3 said:
I thought I'd check in advance of any problems and maybe order a spare only to find that my 4hp Yamaha hasn't got one ... some sort of rubber device instead.
Click to expand...

I think a lot of manufacturers have gone over to those cushioned hubs rather than simple shear pins nowadays, they seem to be less likely to break/fail, but they do cost an awful lot more than a new shear-pin to replace/rebuild if they do. Methinks that this design 'improvement' might be a result of too many unscrupulous customers having had the audacity to use cut-down bolts, welding rods, split pins, etc. rather than buying the OM's very reasonably priced replacement shear-pins like they're supposed to.
 
Cheap as chips, I used to make mine from knitting needles of which my late mother had stacks! No machining necessary because there is a whole range of diameters, just cut to the correct length.
 
Just on the subject of shear pins. Yes they usually break if you have the engine running at fast revs when you throw it into gear. Usually out of frustration at a stalling cold engine. The pin breaks in 2 places so 3 pieces. In an emergency you can refit 2 pieces so that you get drive. But be very careful. Works in this case on an old Johnson 6. olewill
 
I love this thread! A load of people who can afford something to put the outboard on in the first place, looking to save a couple of quid making their own shear pins! Now THAT'S "practical" boat owning! Funny enough, having had our Suzuki 2.2 for nearly 20 years, I've just this season had to fit the second spare pin that came with the engine when we bought it, so I've ben wondering about getting round to sourcing a replacement. I don't know what ours was made of, but if it was brass, it had been chromed afterwards, because it looked "silver". Also appeared to have quite a fine almost "ground" finish and there was a tiny little score line round the middle of it.
 
Actually, just looked on eBay, and Pacer marine are selling what they claim to be two genuine Suzuki shear pins and a prop nut split pin for £3.79 with free postage, so I can't really complain at that.
 
Avocet said:
I love this thread! A load of people who can afford something to put the outboard on in the first place, looking to save a couple of quid making their own shear pins! Now THAT'S "practical" boat owning.
Click to expand...

And that is an excellent example of how some of us practical boat owners can afford to have boats.:D
 
Oh, how I envy boaters discussing shear pins!

My Yamaha 3 hp Malta has a rubber part glued to propeller body and splined bush. In case of hitting an obstacle this part is supposed to breack free and I was told that a complete new spare propeller is needed to keep on motoring.
It looks unbelieveble from a Maker as Yamaha.

Sandro
 
Sandro said:
Oh, how I envy boaters discussing shear pins!

My Yamaha 3 hp Malta has a rubber part glued to propeller body and splined bush. In case of hitting an obstacle this part is supposed to breack free and I was told that a complete new spare propeller is needed to keep on motoring.
It looks unbelieveble from a Maker as Yamaha.

Sandro
Click to expand...

Are you sure about that? Lots of propellors use rubber cush drives .... both my saildrives and my Suzuki 2.5 outboard for example ..... but they are designed to absorb impacts rather than destroy the drive. I've caught my Suzuki prop on rocks a couple of times at lowish revs and stalled the motor but the prop is still fine, if a little scraped!

Richard
 
Here are some random gleanings from years cruising often spent in places where there is no spares supplier on hand.

Brazing rod makes a good makeshift shear pin. Fence wire will do at a pinch but will rust quickly. Both are easy to file down to a fit if required. Stainless is not.

If you have a rubber hub and the prop has spun on the hub several self tapping screws screwed into the rubber can give you limp home capacity. NB the prop will spin again if you rev it!

Replacing the rubber hub is an option if the prop is still good. As well as the manufacturers hubs there are aftermarket suppliers eg http://www.solas.com/newweb/propeller/products/access.asp

The rubber insert requires a considerable force to fit. A hydraulic jack with a frame works. A mandrel may be needed, a socket will often be a suitable substitute. Always ask the locals if you are stuck. They usually know the 'fix it' guy.

If you are heading to the Caribbean and swithering about which make of OB to buy Yamaha is the local's weapon of choice in most islands. Avoid Suzuki.
 
Last edited:
reeac said:
Years ago I sheared one by engaging gear at a fast idle and the chandlers had a choice of strong ones (s.s?) or weaker ones. Seemed a pity that the customer had to choose. I went for the strong one.
Click to expand...

This may also depend on the prop material (some come with a choice of plastic or aluminum). You should use the brass with the plastic prop, is my understanding.
 
RichardS said:
Are you sure about that? Lots of propellors use rubber cush drives .... both my saildrives and my Suzuki 2.5 outboard for example ..... but they are designed to absorb impacts rather than destroy the drive. I've caught my Suzuki prop on rocks a couple of times at lowish revs and stalled the motor but the prop is still fine, if a little scraped!

Richard
Click to expand...

No, I said "I was told...", I am not sure and hope to be wrong. As I understand, the rubber bush should initially damp the schock by elastically deforming and only in extreme case should part before damage can be done to motor parts.
I devised something similar to the screws suggested by TQA but am wondering about the alignement of propeller and shaft by a broken rubber bush.
I miss the Seagull way, still better than shear pin: propeller steadily fitted on shaft but free to spin, and a spring transmitting motion between the two.
I'll search further information from Yamaha people.

Sandro
 
Sandro said:
Oh, how I envy boaters discussing shear pins!

My Yamaha 3 hp Malta has a rubber part glued to propeller body and splined bush. In case of hitting an obstacle this part is supposed to breack free and I was told that a complete new spare propeller is needed to keep on motoring.
It looks unbelieveble from a Maker as Yamaha.

Sandro
Click to expand...

These can be rebuilt for ~ $25. Yes, a spare is the best solution, since I have spun several over the years. You need to do something like wind in a crab trap rope at full throttle. They do prevent damage.
 
You must log in or register to reply here.

Share this page

Top