Re: [OMC-Boats] Need help with Props, Thrust Washers 1970 Sportsman

Also, any decent prop shop could refurb, rebalance, even re-pitch your
OMC prop., making it as good as new. Check your yellow pages.

On Jun 7, 2009, at 7:47 PM, Andy Perakes wrote:

> A washer's primary job is to spread load over a larger surface area
> to prevent localized loads from exceeding materials limits. Fairly
> significant impact loads can be generated when the drive is engaged
> (forward or reverse). In these cases, the thrust washer's job it to
> take very high localized loads from the pin (a theoretical line
> contact about 1/4" long and infinitely thin) and distribute them
> over a larger surface area on the prop. (You probably know this, but
> you always want to spread loads over the largest possible area to
> minimize the pressue (i.e. lbs per square inch) -- think about snow
> shoes.) The washer is made from a material more forgiving to these
> loads whereas the prop is made from fairly brittle aluminum. The
> failure mode I would expect to see without the washer is for stress
> cracks to appear where the pin contacts the prop. These would
> appear over time and eventually could propogate to the point of prop
> failure, but that would take awhile and you'd most likely notice
> noise or vibration and catch the problem before the prop completely
> failed. It does look like you have a little wear from the end of
> the pin striking the prop (caused by the extra gap due to the
> missing washer), but if you don't see any surface cracks in the prop
> and everything else looks good, I'd put it back together (with the
> washer, of course) and not worry about it.
>
>
> ----- Original Message ----- From: "William R. Lindow, DMD" <williamlindow@...
> >
> To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...
> >
> Sent: Sunday, June 07, 2009 8:56 PM
> Subject: [OMC-Boats] Need help with Props, Thrust Washers 1970
> Sportsman
>
>
>> It appears that my prop has been running without a thrust washer.
>> What damage could happen without it. My original OMC prop is pretty
>> chewed up so I wanted to replace it. It is the white one in the
>> pictures. What is the missing thrust washer supposed to do? The
>> first prop I bought is a new Michigan prop 14x16 012092 that is
>> supposed to fit however the back inside is different than the OMC
>> prop. The next prop I bought is a Michigan prop 14x18 012093 PR 124
>> and it looks similar on the inside but has two channels running
>> through it which the original does not. Hopefully the pictures may
>> help someone figure this out for me.
>>
>> Thanks,
>>
>> Bill
>>
>>
>>
>>
>>
>>
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Received on Monday, 8 June 2009