Not a normal spun hub

[MagothyMike]

The washer end of the torque hub has "coned" out. Last season the boat (1999 Trophy 2352 Mercruiser Alpha 1 5.0) lost speed. I pulled the hub and found the hub coned out on the back section. The locking side was still intact. I replaced the hub assembly and tested the boat. Speeds returned and I hoped all was well. This season after a few fishing trips I accelerated but couldn't get the boat to go over 4100 rpm (in idle engine will red line) at 21.5 mph (GPS). I pulled the boat and inspected the hub. Once again the rear section of the hub displayed signs that it was again on its way to coning out. I can't find any play in the shaft and the thrust washer looks fine. The prop is a three blade aluminum 15 inch with 17 pitch. except for being under water it shows no obvious signs of damage or distortion. It seems to me that in order to create this fault, either the prop or the shaft are wobbling during load, and this wobble creates the coning out of the rear section of the hub. Sort of like exaggerating a drill bit around and around to hog out the initial diameter. Any ideas expressed would be terrific!
BTW, the boat has not over heated or displayed any other running troubles. Temp is steady ay 175.

 

[hwsiii]

Re: Not a normal spun hub

Mike, send us a picture of the prop hub so we an actually see it and see exactly what you mean.

H

 

[MagothyMike]

Re: Not a normal spun hub

Hopefully this worked.
The left side hub is the one I removed yesterday. It shows signs of coning out. The right side is the hub from last year. As you can see it is really coned out. What I don't understand is the front section that has the grooves for the shaft spline washer is still intact.

 

[frankie g]

Re: Not a normal spun hub

thats what mine looked like exactly, when I changed my prop and hub. mine was off a150 saltwater Merc. on my 2302 Trophy. I ended up with a Apollo SS 14 3/8 x15 vs the stock alum. merc prop, it made a good bit of diffence too!

 

[MagothyMike]

Re: Not a normal spun hub

Any thoughts, ideas, opinions?

 

[frankie g]

Re: Not a normal spun hub

why do you think that its not normal??? 2 the same! different engines, Mines an OB. looks like a spun hub to me!

 

[MagothyMike]

Re: Not a normal spun hub

I believe it is abnormal because it is the rear side of the hub, not the slotted end. I am trying to find out if others have had the same symptoms and what their remedy was. A spun hub to me is when the slotted end gives way. If this isn't the case then please bring up to speed. Thanks for all the replies.

 

[frankie g]

Re: Not a normal spun hub

got me ! my old hub looks exactly like your bad one. had mine for 5 yrs. I'm glad I bought a SS prop and new hub or probably would had got stuck out on the blue. If it's out of the ordinary I'd like to know also

 

[MagothyMike]

Re: Not a normal spun hub

The spline coupling dog ears into the plastic flo torque hub. The prop shaft, once through the spline coupling doesn't touch the hub. So I can't figure out what would cause the hub to "cone out" if it doesn't come in contact with the shaft. If the shaft was wobbling I could surmize that a lathe effect was taking place and the shaft was wiping out the hub. But the shaft is in place without any signs of failure. Lasy season I blamed the failed hub on a slow moving mud bar hit. (Barely above drifting speed). I have no reason as to why the hub would have failed the exact same way. I've heard of fishing line causing trouble like this. Could I have picked up some line while running and this in turn caused the problem? No line was on the shaft when i removed the prop, of course it could have ran itself off long ago.

 

[frankie g]

Re: Not a normal spun hub

well, I ran aground (sand bar) 2 x's, at idle speed in the coarse of 5 yrs, maybe that's just howw they look