Prop Shaft Operation - What Holds It ?

[rpeebles]

I have a 2GM20F with reverse drive and PSS seal. Is the prop shaft "held in place" by the transmission and the cutlass bearing? Does the shaft log constrain it? I am guessing it is just the tranny and cutlass bearing as water must move up the shaft log to cool the PSS. Thanks, Roger

[Cheechako]

Held in place...? You mean from sliding out of the boat? That would be the engine coupling. The cutlass bearing holds it concentric to engine output centerline...

[cal40john]

What do you mean by hold it?

What keeps the shaft from sliding out the boat while in reverse is the screw in the side of the coupling flange. Since you have the PSS the SS collar gives you a second chance.

If you mean what keeps it aligned. It is the cutless bearing near the prop and the coupling flange.

The PSS is on a flexible bellows big enough around that it doesn't do anything. Regular stuffing boxes are mounted on hoses to self align.

Long shafts will have a pillow block. Some people use flexible couplers to reduce the tolerance of alignment.

John

[daddle]

Yes. Axially, the thrust is taken by the transmission output bearings. Radially, the cutlass bearing and transmission bearing take the loads. The shaft log holds the shaft seal and sometimes the cutlass bearing.