1982 Johnson 4.5

I was looking at the breakdown of the lower unit when I discovered something that has me perplexed. When changing/replacing the prop it lists prop hub, cotter pin, drive pin and thrust washer!!
I purchased my motor used a bunch of years ago and have had the prop off several times over the years.Ive never seen a thrust washer or knew there was suppose to be one.
From the diagram it shows it between the drive pin and the prop hub. To me it don't make sense, because the prop is pinned to the drive shaft already (in the front) and can't move front or back. Can someone explain just what it's purpose is?

It's ran fine all these years without it, but I've ordered one anyway.

That thrust washer.... as I remember, it goes between the drive pin and the prop... for what purpose, I have no idea.

joereeves said:

That thrust washer.... as I remember, it goes between the drive pin and the prop... for what purpose, I have no idea.

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Yep, your correct on that Joe. They put it there for a reason and all I'd like to know is why. Like I said, it don't make sense to me.

Perhaps to let the prop spin against a washer rather then the pin should the hub start to slip.

joereeves said:

Perhaps to let the prop spin against a washer rather then the pin should the hub start to slip.

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Now that's a thought. I'd never considered that. It's hard to believe hat you could ever trash a hub on such a small engine.

I believe the washer is intended to allow the shear pin to break before something else does