Is there a factory setting for props??

[dougs-outboards]

Huh?? What is this guy talking about.

I have noticed thru the years that props with good hubs (not spun) are always in the same basic position, and that the spun hubs are in a different position.

Let’s take a trip together in our minds shall we? (Not like back in the 60’s where you took a trip and never left the farm… 🙂

Ok, if you were to place a good prop in front of you, looking at the slot in the hub where the pin goes, and the prop is in a "Y" position, the hub is always crossed (horizontal, not vertical).

My thinking is that when you go to put your prop on, the "Y" shape makes it easy to push the prop on with no resistance from other things in the way. The intake snout goes easily between the top 2 blades as the prop goes on, and the hub is horizonatal to accept your waiting horizontally placed shear pin. After all we don’t put the shear pin in vertically as it tends to fall out.

This is a good way to identify a blown hub at first glance, (along with the other signs of hub spinnage).

Look on some of your good and bad props and report with your findings.

Anybody know anything about this or is it one of the mysteries of all time?

[garry-in-michigan]

You can check your prop for proper clutch operation if you have a big torque wrench . . . 🙂

[fisherman6]

quote Dougs Outboards:

Huh?? What is this guy talking about.

I have noticed thru the years that props with good hubs (not spun) are always in the same basic position, and that the spun hubs are in a different position.

Let’s take a trip together in our minds shall we? (Not like back in the 60’s where you took a trip and never left the farm… 🙂

Ok, if you were to place a good prop in front of you, looking at the slot in the hub where the pin goes, and the prop is in a “Y” position, the hub is always crossed (horizontal, not vertical).

My thinking is that when you go to put your prop on, the “Y” shape makes it easy to push the prop on with no resistance from other things in the way. The intake snout goes easily between the top 2 blades as the prop goes on, and the hub is horizonatal to accept your waiting horizontally placed shear pin. After all we don’t put the shear pin in vertically as it tends to fall out.

This is a good way to identify a blown hub at first glance, (along with the other signs of hub spinnage).

Look on some of your good and bad props and report with your findings.

Anybody know anything about this or is it one of the mysteries of all time?

This is true. The factory hubs that I have seen are set this way and I assume for this reason. Test wheels are the same way. The drive slot in the hub is set horizontally when the notch to clear the exhaust snout is at 12 o’clock.
-Ben

OldJohnnyRude on YouTube

[garry-in-michigan]

The rubber clutch is designed to slip when you hit something to save the drive pin. So the blade orientation may be shifted and the clutch still be good. The condition of the blades is a better indication of clutch damage. Although shifting at too high a speed can damage the clutch without damaging the blades. So if you are buying a used prop and the orientation is wrong, check the slip torque. If it is at the low end, figure the cost of a new hub into the price. . . 😉

[dougs-outboards]

Thank you for the great info there Ben and Garry. (Also love your ice cream 🙂

I thought there might be a method to their madness on the prop orientation thing.

Doug

[amuller]

Looking at the table, the 50 hp Starflite has a higher slip clutch torque than the 75 hp. Is this correct, or is it a misprint?

[garry-in-michigan]

No misprint, they have different gear ratios . . . 🙂

[Author]

Posts