1973 Johnson prop slide

[bobsquatch]

I just bought a 1973 Johnson 115 the only thing that seems to be off about it is that the propeller slides more than an inch fore and aft on the prop shaft upon which it snuggly fits. My question is this. should it be shimmed into place or is it a free-floating propeller?

 

[achris]

With the prop NOT on the shaft, how much 'in-out' movement is there (of the shaft)? Any more than about 1/8" is too much....
If the movement is between the prop and the shaft, then you may have the wrong thrust washers on, or the wrong prop.. And just because it came with that prop doesn't mean it's the right prop....

Chris.......

 

[bobsquatch]

Thanks Chris, the play is between the shaft and the prop. I will research the correct prop for this motor and xteference to what I have and report back.

 

[racerone]

Sounds like the thrust washer is missing.

 

[bobsquatch]

Thanks racerone. There is no play in the shaft. There is 3/8"+ between the nut and the prop. Prop is an unknown manufacturer aluminum 13X19. I just ordered the service manual this morning so that will help get me going. In the meantime does anyone have a diagram or list in order of assembly for the prop components?

 

[gm280]

According to the manufacturer's break down parts list for that year engine, and it seems they only made one series of the 115 HP that year, there is both a thrust washer and a prop spacer in the parts list. If you have only the prop and nut and cotter pin, then you are missing some parts. The proper thrust washer is part number 0318841 and the spacer is 0315810 and the actual prop part number is 0382763 and is a 13 3/4 by 17 size. There are other props number as well and you can research them and see what yours is...

 

[bobsquatch]

The thrust washer is the large one and the spacer is correct. Forgive my ignorance but what is the function of the thrust washer. The large one in my setup is numbered 390896 and it looks as though the small spacer washer is missing. This is not likely the original prop but it is within specs for the motor. Since this is a very light boat the extra pitch should play out nicely for economy and occasional speed. I am guessing high 40's from a 1000lb boat. We will see. When set up correctly how much play should there be? On my 1990 88hp there is a small amount somewhere between 1/8 and 1/16. Probably the lesser. I can just barely move it..

 

[bobsquatch]

Well after further investigation I discovered the 390896 number I gave is actually the prop, the spacer is missing and the thrust washer is forward of the prop and rides inside the hub. Should I order the spacer online or will the local dealers have a drawer full of them?

 

[gm280]

Again according to the break down, the thrust washer goes on before the prop, then the prop and then the spacer after the prop. Hope that helps you out a little. If you don't have the spacer, buy one and your sliding prop will not be sliding anymore...

 

[bobsquatch]

Yep. I ordered one this morning seven dollars for $.49 spacer but it will be delivered in a day or two and save me the hunt.

 

[Texasmark]

To give you a relative idea, if you have a splined prop shaft (I did on my '72 125 Johnny) the prop needs to be tight, somewhere around 50 ft-lbs...don't have the spec but my 90 Merc torqued to 55. Slop in the prop will cause unnecessary noise and wear of the drive components.

Also, if the prop shaft and thrust washer are tapered, ensure that the slopes of the tapers are lined up. Then once you install your spacer and the prop, the prop shaft protruding out behind the prop hub will only be threads. If any smooth space, you still aren't setup right.

Answering your question as to the function of the thrust washer, it's to contain the thrust of the prop. If it weren't for that your prop would move up and into your gearbox tearing thins up when in F gear.

Mark

 

[gm280]

Actually the thruster washer buffers the prop from riding on the two prop shaft seals. So it has a function. And the prop spacer takes up the slack to eliminate the sliding issue...

 

[racerone]

Forward thrust of the prop is transferred to the propshaft via the thrust washer.---Then the thrust is put to the forward gear .--Then the thrust is transferred to the gearhousing via the thrust bearing on the forward gear..

 

[bobsquatch]

Thanks guys.