prop thrust washer - WHY here?

[adamsnez2]

hey guys!
im confuuused about this one.
1965 Evinrude, 33hp.
Parts manual shows installation in this order;

PROPCOVER > DRIVE-PIN > THRUST WASHER > PROP

From what I've read elsewhere, your thrust washer should go between the gearcase and the prop, WHY is my manual showing it on the far side of prop, and not between it and gearcase?

As per my usual threads, i have a couple questions [in the learning process]

1) My driveshaft doesn't have any splines, were all OLDER o/bs splineless and the driveshaft just spun by the drivepin??? Seems so.

2) Picture attached to refer to this question, i took it apart and only found the following pieces.
PROPCOVER > DRIVE-PIN > PROP..... Where is my thrust washer!?? Im not sure if it's just jammed INSIDE the prop, i dont know if that middle section contains the thrust-washer and a couple other small circular pieces [mentioned in the manual, just saying that because it doesnt show what piece is on the prop side, and which circular parts are IN the gearcase]

I dont wanna be running without a thrust-washer, even though the prop doesn't hit the gearcase or exhaust port
THANKS!

 

[Willyclay]

Re: prop thrust washer - WHY here?

Yes to Q1, the older models had splineless prop shafts and the prop was protected by a "shear pin" until slip-clutch prop hubs came along, like yours, and the pin was re-engineereded as a "drive pin". Q2 regarding the thrust washer, yours installs over the bronze prop hub prior to installing the drive pin. No washer needed forward of the prop. Check this out below:

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/278648/27864800001.htm

 

[jimmbo]

Re: prop thrust washer - WHY here?

The washer is there to prevent the prop from sliding backward on its rubber slip hub in case of impact. If the prop were to slide back even an 1/8 inch it would be next to impossible to easily remove the drive pin. The pin is made of Stainless Steel and while it is not easy to shear, it occasionally does bend making it difficult to remove.

 

[adamsnez2]

Re: prop thrust washer - WHY here?

so all this time i've been running the motor without the thrust washer? [between prop cover and prop itself] !!!!???!!!
that's how i read your post Willy.

PS: What exactly is a prop hub; the parts that fit INSIDE the "tunnel" on the prop?

thanks for the info btw guys.

 

[Willyclay]

Re: prop thrust washer - WHY here?

[between prop cover and prop itself] !!!!???!!!that's how i read your post Willy. PS: What exactly is a prop hub; the parts that fit INSIDE the "tunnel" on the prop? thanks for the info btw guys.

NOT between the prop cover and the prop! Install it after you install the prop but prior to inserting the drive pin. Should there be any displacement of the prop on the hub, the washer will maintain the correct spacing. Yes, the hub is the "insides" of the prop. If you look at your prop, you will see two very different looking metals. The prop blades and housing (tunnel) is made of an aluminum alloy. The hub part you can see is bronze. The hub part you cannot see is a rubber sleeve around the hub that will slip when torqued beyond the design spec. This design replaced shear pins from the days when the entire prop was brass or bronze and had a lot of rotating mass. Economics drove the change as aluminum became much cheaper after WWII and shear pins also got pretty flimsy before slip-clutch hubs were perfected. The hub is fitted by a hydraulic press and will protect the spendy parts of the drive system such as the prop shaft, gears, driveshaft, crankshaft, etc. Your motor is old enough that you might expect to experience a failed hub soon. The rubber deteriorates and allows the prop to slip when it is under load. The first time it happens it will be a little weird because everything looks okay. If you suspect a slipping hub, make a Sharpie mark on the prop housing/tunnel in-line with the drive pin ends. Try it in the water again and see if the marks are no longer in alignment with the drive pin. If so, you can have your prop re-hubbed.

Hope this helps. Good luck with that great old motor!

 

[adamsnez2]

Re: prop thrust washer - WHY here?

thank you SO much, no more questions. More knowledge to me!
Thanks again, Willy !!!!