Volvo SX-M Thrust Bushing

[wade0510]

I am working on getting my Volvo SX-M drive in running condition in order to get the boat back on the water. The boat came with two props, one aluminum and the other Stainless Steel. I have gotten the bearing carrier and propshaft installed with all seals in place, but when looking at the exploded view, I noticed a tapered washer (Thrust bushing?) that was supposed to go behind the prop. Looked through my parts bucket, and it was not there, and my FIL (Father-in-law) who helped me disassemble it does not remember one being there. I have read something to the effect that (maybe?) the thrust washer is attached to the prop.

I should add that my aluminum prop slides down the splines cleanly, but the stainless steel prop gets hung up with about a quarter to half inch clearance from the gear housing. I am wondering if the stainless prop has the bushing built in, while the aluminum does not? I have the lower off of the boat right now, and will post some pics up tomorrow of both the stainless prop and the installed aluminum prop. Thanks for any help guys.

 

[jestor68]

Re: Volvo SX-M Thrust Bushing

It's called a thrust washer. It goes on before the prop goes on. Make sure it's not stuck on the back side of one of your props.

Different brands of props can use different(thickness) thrust washers.

 

[bnicov]

Re: Volvo SX-M Thrust Bushing

Is it on the shaft?? They get stuck on there pretty good. Also, the stock VP props have a different thrust washer than the aftermarket props with the removable hubs. The stock VP tw, is bigger than the aftermarket and won't work with aftermarket props with removable hubs. I ran into that last summer when changing out my 21p VP prop for a 23p aftermarket (I now run a 21p 4 blade that is great).

 

[wade0510]

Re: Volvo SX-M Thrust Bushing

The aluminum prop is a genuine Volvo Penta prop, the one that came on the drive I'm sure. The stainless steel is a renegade prop. The stainless prop is also about 1/2",, maybe 3/4" shorter than the aluminum prop, maybe this explains the gap with the stainless installed?



Here is the aluminum prop installed. No gap, and don't know if there should be one there or not. When I install the stainless steel prop, there is a gap at the end (about 1/8") between prop and gearcase.


View of just stainless prop, which was previously installed on the drive when the boat was purchased


Both props side by side. Upon further inspection, I noticed that both have a slight recess/bevel around the center. Is it possible that the thrust washer/bushing is built into the prop?


These are the parts that the exploded view via Volvo parts catalog shows going in front of the prop. The largest washer at the top of the photo has splines inside.


Here is the propshaft. As you can see, there is no washer still on the shaft. I had a man who's a bit more experienced than me tell me that the bevel on the shaft stops the prop from going too far up the shaft. I don't know what to think.

 

[wade0510]

Re: Volvo SX-M Thrust Bushing

Here is the exploded view of the drive. I think I may be missing part 47, but that could also be part of my hub. I think my thick splined washer is part 40.

 

[Don S]

Re: Volvo SX-M Thrust Bushing

The thrust washer is not in your props.
The thrust washer sits on the tapered section of the prop shaft and the hub of the prop goes up against it.

 

[wade0510]

Re: Volvo SX-M Thrust Bushing

Not that I am planning on it, but what would happen if one were to run a drive without the thrust washer? I am only asking because I have to wonder if there has ever been one on this drive?

 

[Don S]

Re: Volvo SX-M Thrust Bushing

In your picture, you want item 41, not item 27.
The parts will look like this.

 

[Don S]

Re: Volvo SX-M Thrust Bushing

Not that I am planning on it, but what would happen if one were to run a drive without the thrust washer? I am only asking because I have to wonder if there has ever been one on this drive?

It would grind the lower housing down.

 

[jestor68]

Re: Volvo SX-M Thrust Bushing

Not that I am planning on it, but what would happen if one were to run a drive without the thrust washer? I am only asking because I have to wonder if there has ever been one on this drive?

By the time you got back to the dock; assuming you were no more than a 1/2 mile away, you would be purchasing a new lower unit. :facepalm:

 

[wade0510]

Re: Volvo SX-M Thrust Bushing

Alright, thanks so much Don. I'd like to get this thing done the right way, and not have to worry about any problems later on down the road. I am going to look around again and see if I can't find the part in the shop somewhere, but I do not believe that there was one on this drive to begin with.

One more question. In my first picture, you can see that the prop fits up inside the gearcase. Should it fit right there or should there be a gap? When I was searching through the forums, most people seemed to say that the washer that I am missing will keep it out of the housing, and if it does fit inside there it will grind as Don said. Any comments on this?

 

[Don S]

Re: Volvo SX-M Thrust Bushing

The thrust washer also keeps the prop centered on the shaft. Get the washer install it and that is what it's supposed to look like.

If you tried to tighten the nut down without the thrust washer the prop wouldn't even turn, and NO, you don't back the nut off until it turns either. The thrust (remember that word) from the prop pushes the prop forward, it's whats makes the boat move. Thust the THRUST washer is what keeps the prop from hitting the housing.