Output shaft slop

[HPwannabe]

Seems like my last few questions are about how things fit. Question now is about output shaft fit. Is there any rule of thumb or guideline about how much play is allowable in this joint? I know the right answer is probably “none”, but this unit has operated fine for years and I don’t think there is a problem. The splines on the shaft are of course shiny on the thrust side, but there’s no visible evidence of significant wear. See the picture - I can rock the shaft to creat about 1/8” or so of play at the u-joint end.

 

[HPwannabe]

I see the photo didn't come through. Here's the pic.

 

[Alumarine]

Are the grooves/teeth in the coupling and the shaft square?

 

[HPwannabe]

Not sure I follow the question. They are not absolutely square, they are slightly tapered (typical splines). Maybe I’m missing the question.

 

[Bondo]

Not sure I follow the question. They are not absolutely square, they are slightly tapered (typical splines). Maybe I’m missing the question.

Ayuh,...... The tops of the splines should be flat, square, Not Pointy,.....

 

[HPwannabe]

Oh, yes. Flat. As mentioned, I don't see any evidence of undue wear. It's hard to inspect the power hub splines, but I'll clean them up and have another look. I'm wondering if there might be a spec available on the "backlash". I can't find anything in my service manual.

 

[HPwannabe]

Oh, yes. Flat. As mentioned, I don't see any evidence of undue wear. It's hard to inspect the power hub splines, but I'll clean them up and have another look. I'm wondering if there might be a spec available on the "backlash". I can't find anything in my service manual.

Here’s a pic of the shaft splines.

 

[Alumarine]

I can't speak to the slop but if the splines in the coupler look like that I would think it's fine.
I've never checked it the way you did.

 

[HPwannabe]

I can't speak to the slop but if the splines in the coupler look like that I would think it's fine.
I've never checked it the way you did.

Thanks marc c. I'm thinking the same thing. I think one of the important things would be that there's no visible difference in the profile of the splines in the areas just forward and aft of the zone which engages the hub. You can see that zone, due to the shininess of the thrust surface on the splines, but there's no obvious thinning of the splines. I'll be looking at the hub splines this evening.
Separate question - I'm assuming I can use the output shaft as an alignment tool when I reinstall the engine and gimbal housing. Are there any issues with that? I realize that a "real" tool would probably be much easier to "read" because the grease marks will be more obvious on a smooth shaft. But I think I ought to be able to use the shaft if I get everything scrupulously clean, and take care in the process. Anybody ever do it that way?

 

[nola mike]

Thanks marc c. I'm thinking the same thing. I think one of the important things would be that there's no visible difference in the profile of the splines in the areas just forward and aft of the zone which engages the hub. You can see that zone, due to the shininess of the thrust surface on the splines, but there's no obvious thinning of the splines. I'll be looking at the hub splines this evening.
Separate question - I'm assuming I can use the output shaft as an alignment tool when I reinstall the engine and gimbal housing. Are there any issues with that? I realize that a "real" tool would probably be much easier to "read" because the grease marks will be more obvious on a smooth shaft. But I think I ought to be able to use the shaft if I get everything scrupulously clean, and take care in the process. Anybody ever do it that way?

The important part is not the shaft wear, but the coupler wear. IIRC they're aluminum or something significantly softer than the shaft. And no, you can't use the shaft as an alignment tool. The tolerances are tighter on the tool.

 

[Scott06]

You’re fine those splines look great, no wear at all.
the u joint end you are rocking is supported by being in the gimbal bearing when installed and properly aligned in the boat.

 

[HPwannabe]

Thanks everyone for the replies. I guess I’ll need to find me an alignment tool. Meanwhile here is the output hub. It looks pretty good to me. I think the alignment in this system was really good, and wear has been nominal.