Misalignment or expected lifespan?

[96superjet]

Three seasons in my Superjet with JetManiac 781 big bore, 44mm carbs sitting on Protec intake and running 10/16 hooker prop.

So is the stripped out spline due to mis alignment (I didn't have my Cold Fusion alignment tool back when I put this ski together) or is three seasons expected life cycle with modded motors?

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[DAG]

Bad alignment in the SJ

 

[augustaf]

Yes, misalignment would cause more wear, but this seems to be a case of worn o rings inside the midshaft. Once these o rings fail, water will (!) wash out the remaining grease, causing rapid failure. I have made it a point to remove the midshaft and r&r o rings whenever the engine is removed. They don't last all that long with grease on one side and water on the other.

 

[96superjet]

Luckily I had already built another Solas 144 mag pump for my FootRocket build, so I'm just swapping stuff around. My original prop is a Hooker 10/16 (left) and the one on the right is a Skat Trak that I had them make similar to a 10/16. Can't tell if you can see from the pic, but there seems to be a reasonable difference in the curve of the leading edge.

Also the cones that came with my Solas Mag pumps are significantly different. The original one I bought (stubby cone) was from Fast Elements. The second one I bought was MarinePartsHub.com. I hope I don't have bearing problems with it :-/

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[Freakrider]

Also recommend more spline overlap by pressing in midshaft while running an additional spacer washer after coupler and don't worry about a little more coupler gap up to 1/4 inch ( no problems in my experience ). Your midshaft orings have worn a groove into the shaft which normally happens slowly but because of your grooves now, it is even more crucial to replace orings in midshaft often to prevent grease washout.

 

[augustaf]

Luckily I had already built another Solas 144 mag pump for my FootRocket build, so I'm just swapping stuff around. My original prop is a Hooker 10/16 (left) and the one on the right is a Skat Trak that I had them make similar to a 10/16. Can't tell if you can see from the pic, but there seems to be a reasonable difference in the curve of the leading edge.
Keep in mind, the splines of the midshaft are also worn out. The new one will also require the two o rings (see pic)

 

[96superjet]

Full motor tear out. Put in a new driveshaft/pump assembly and new midshaft and still had to time to get the kid out on the ski so he could practice.

I got to use my Cold Fusion alignment tool for this build and my previous drive shaft install was a pinch low. So I re shimmed the pump and she spot on (I had 3 people put their head in the engine bay and confirm centerness). So I hope to get a few more seasons out of this ski.

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[kevbo]

That is a lot of wear. It usually takes some sand in the splines to get that bad. The shaft tunnel will always have sand laying in it. Guess what happens every time you remove and reinstall the pump. The only way to prevent this is by sliding the engine forward and pulling the short shaft while thoroughly cleaning everything before reassembly.

 

[augustaf]

This pic of a std. length shaft used in an oem housing shows Kevbo's sand theory near the tip of the shaft quite clearly. It's not known to all that the Solas pump positions the shaft about 3/16" (4mm) farther back, giving less spline engagement. If you look at the op's picture you'll note that the front o ring was already compromised by the rearmost part of the splines. This picture shows standard location of o rings. Jetmaniac realized early on- as soon as the Solas pumps hit the market- that a longer shaft might be indicated and proceeded to have them made.

 

[96superjet]

This pic of a std. length shaft used in an oem housing shows Kevbo's sand theory near the tip of the shaft quite clearly. It's not known to all that the Solas pump positions the shaft about 3/16" (4mm) farther back, giving less spline engagement. If you look at the op's picture you'll note that the front o ring was already compromised by the rearmost part of the splines. This picture shows standard location of o rings. Jetmaniac realized early on- as soon as the Solas pumps hit the market- that a longer shaft might be indicated and proceeded to have them made.View attachment 285341

Great point and good information. Earlier Freakrider suggested adding an addition spacer washer when installing the coupler on the midshaft threads. Hence allowing you to press the shaft further back through the housing and affording both better driveshaft overlap while still having good coupler to coupler engagement. This is the reason I come to this forum. Great information.


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