Will these 2 different props fit Yanmar SD20?

[Wanderlust]

I have two props but the centres look quite different. Do they both suit a Yanmar SD20?

In the spares that came with my boat was a used propeller with a chewed out bush, and I kept it with the thought of getting it repaired. Then I found a cheap new on on eBay so bought that. When it arrived, I compared it to the chewed one, and they look quite different.

The new one is marked 850342 which is the old model number for what I believe suits the SD20. The old one has a lip machined in it and seems to have a surface for load bearing (now damaged), while the new one is painted. I am assuming the splined inner section is at a different level due to the broken rubber bushing.

Can anyone familiar with these advise if they are both compatible.

Also, it appears now that the old one will not be an economic repair, so I am looking for another 16 x 11 left hander.

[MARINE ENGINNER]

Originally Posted by Wanderlust

I have two props but the centres look quite different. Do they both suit a Yanmar SD20?

In the spares that came with my boat was a used propeller with a chewed out bush, and I kept it with the thought of getting it repaired. Then I found a cheap new on on eBay so bought that. When it arrived, I compared it to the chewed one, and they look quite different.

The new one is marked 850342 which is the old model number for what I believe suits the SD20. The old one has a lip machined in it and seems to have a surface for load bearing (now damaged), while the new one is painted. I am assuming the splined inner section is at a different level due to the broken rubber bushing.

Can anyone familiar with these advise if they are both compatible.

Also, it appears now that the old one will not be an economic repair, so I am looking for another 16 x 11 left hander.

can you make a better picture at the bush to the used one?

[Wanderlust]

Originally Posted by MARINE ENGINNER

can you make a better picture at the bush to the used one?

Thanks for the interest. How is this? I'm now wondering if the nicely machined lip was part of the damage, rather than design.

[MARINE ENGINNER]

Originally Posted by Wanderlust

Thanks for the interest. How is this? I'm now wondering if the nicely machined lip was part of the damage, rather than design.

yep it is damage. i have never seen propeller on a yanmar saildrive with a groove like this and i am thinking that you are missing a washer on the shaft that's why you have this groove the propeller was touching a lip on the casing of the saildrive. you will see also the groove is polished and the lip around is corroded so it means that until the last moment the propeller was "machined" on the casing
check the manual you will see the parts first goes metal washer with spline same as the prop washer and then propeller , teflon washer , cone nut etc.

[hugosalt]

I replaced my fixed props with a folding prop on my SD 20 years
ago, but still have old props in basement...
I have looked up my old prop #'s in my boats maintainence book and my old part # for a Volvo 14/9 LH is #850341-9 close to your #. (was original with boat when new)
The other thing that catches my attention is that the splines/bushing on your spare are install opposite than your
replacement prop, the replacement prop is correct as it the same as on my old prop (will send pictures tonight).
Enginneer is correct, bushing should be flush as your new prop,
but again splines are on opposite side of prop as in your picture.
Hope this helps,
Hugo

[Wanderlust]

Just to update this old thread, as I referenced it in another one re a lost prop ....

Marine Enginner was correct, that the "machined" lip was caused by damage, and not by design. The splines are correct, not reversed as suggested by Hugosalt.

What has happened, is that the rubber bush must have slipped or broken, allowing the blades component to move forwards nearly an inch, and rotate against the saildrive hub. The rubber bush must have still provided enough friction for power to be transmitted ..... I can't rotate it by hand. The grooved "lip" would have been machined out by the stainless retaining screws on the saildrive hub.

Obviously you would expect damage to the saildrive, however there is no evidence of that. One of those mysteries you find in the spares cabinet.

[Sailorman Ed]

On the oft chance someone might have one, I am looking for a spare prop for the SD20.
Ed