Midshaft heating up?

[Snguy1214]

Just swapped a 701 from one hull to another. Replaced the midshaft housing, splines looked good on driveshaft. I shimmed the pump so the driveshaft was dead center of the thru hull hole. Pressed midshaft 19.5mm everything turned smooth by hand. If I run the ski on the trailer for 15 seconds the midshaft gets pretty warm to the touch, I can keep my hand on it but it’s warm. Is this normal? I followed instructions on here shimming the back of the motor first then the front, coupler has a little less then 1/4” spacing, smooth transitions between couplers on motor and shaft, greased the midshaft and installed new o rings. Should I tear the pump down and double check everything? Or is a little heat normal? Have not had the ski in the water yet ...

 

[JKMike]

1/4" spacing seems a little high for the gap between couplers. The factory spec is 0.079" -0.157".

As for the housing heating up, i wouldn't think it should get all that warm if your only running it for 15 seconds. But I have noticed mine is usually a little warm when I go to flush everything after riding.

Did you use the Cold Fusion alignment tool when you put everything together?

 

[smoofers]

The seals on the midshaft generate a decent amount of heat when the shaft is turning (typical of rotating shaft lip seals). It's only means of cooling are from when it is in the water. It's not entirely abnormal. If it gets REALLY hot, even with the ski in the water, then you definitely have an issue. I had a buddy that ran his ski on the hose way longer than is practical (like 1/4 tank) I won't mention names. Long story short, he destroyed his midshaft bearings and seals.

 

[Snguy1214]

1/4" spacing seems a little high for the gap between couplers. The factory spec is 0.079" -0.157".

As for the housing heating up, i wouldn't think it should get all that warm if your only running it for 15 seconds. But I have noticed mine is usually a little warm when I go to flush everything after riding.

Did you use the Cold Fusion alignment tool when you put everything together?

I did not use the alignment tool, I did do a lot of measuring, I was having an issue with the throttle cable and causing my motor to rev on start up. A brand new midshaft assembly possibly needs a few runs to break in?

 

[Snguy1214]

I did not use the alignment tool, I did do a lot of measuring, I was having an issue with the throttle cable and causing my motor to rev on start up. A brand new midshaft assembly possibly needs a few runs to break in?

It’s odd it seems like the more the motor has ran, the midshaft is not heating up as much as the first time I ran it. I did not mean the coupler gaps, I meant to say spline overlap is about 1/4” from full engagement. I would think just as smoofer said the rubber and friction in the assembly will cause heat. I’ve read a couple posts where some guys Ms were sizzling hot. I do wish I had purchased the cold fusion alignment tool, the midshaft slid on and I didn’t not have to force it on anyone direction to put any of the 3 bolts in...thanks for the replies

 

[SXIPro]

The cold fusion tool is not the be all and end all of alignment. People were aligning motors to pumps for 40 years just fine before CF offered the product. Is it helpful...sure. Is it necessary....no.

 

[Big Kahuna]

If you were able to easily bolt on the midshaft then you are pretty close to perfect, But, you would still be off enough to wear out your splines. As long as you got your engine lined up correctly you should be ok. When New, Yes, there may be some extra heat build up. Regardless, there will always be some heat generated. Grab your hub of your trailer after a long drive........

 

[Snguy1214]

The cold fusion tool is not the be all and end all of alignment. People were aligning motors to pumps for 40 years just fine before CF offered the product. Is it helpful...sure. Is it necessary....no.

When I saw a picture of the tool I wasn’t very impressed, Don’t quote me on this because I’m sure I’m somewhat wrong, but what does that tool offer than using measurements and your midshaft? I don’t know, I’d put that money on something else...if it wasn’t nearly 70$ or I did work skis all the time then it would be a must have tool.
Bigkahuna, I agree. My dumb*** hooked up my carb cable with the carb at about half throttle....thinking I had a runaway motor for a few days I’m sure the heat was excessive because of that. My transitions on the couplers are smooth as hell, and my distance measures the same around the whole motor. I did a lot of reading on this site before I dove into it, took my time, did it once without the rubber thing, got everything straight, did it again after forgetting to grease the tip of the DS, pretty sure it’s solid.
It’s hot out here in Sacramento cent decide if I should go fishing or take the new boat out for a test run