Spun hub at high RPM issue

[DGEXPLORATION]

Hello,
Any ideas on why the hubs keep spinning out at high RPM on my 2009 Yamaha 225 VMAX HPDI? I just bought the boat, a Majek Extreme 22' (shallow bay) from a buddy, who was spinning out prop hubs until he finally kept the RPM's below 4200. I have to think there is a better solution, like a shallower pitch prop? The issue was occurring with both a custom hook 14X20 4 blade stainless, and solas 14X21 4 blade stainless. We do a lot of fishing around oyster reefs, so need to keep stainless.
Any help is much appreciated.

DG

[DennisG01]

Are you sure the hub is actually spinning? Meaning, you have 100% verified the hub is spinning? The other culprit could be trimming the engine too high based on speed/load/conditions or the engine is mounted too high on the transom and it's ventilating.

[DennisG01]

Oh... of course, if you keep crunching through oyster reefs, well... that could very well be your problem right there as it would damage the hub.

[DGEXPLORATION]

I am sure the hubs are getting spun out, as we could only limp home on a couple of occasions, and we didn't hit anything. Man, I'd say the engine is mounted correctly. It was mounted on a 10" hydraulic jack plate one of the bigger Majek dealers in TX, but I'll think about that
Thanks

[DennisG01]

Well, hubs don't just "spin out" for no reason... unless they're old or there is a defect. But once it spins once, it spins easier and easier until you get it rebuilt.

The height thing wouldn't be an issue at those "limping" speeds (unless you have it jacked up way too high). So that leaves either damage to the prop (oyster beds?) or defects in the prop hub.

Growth on the hull bottom could cause this, too - but not likely at that lower limping speed - and it certainly wouldn't change things within a day.

FYI, you can match mark the rubber hub to the metal hub to fully verify, if you want.

[99yam40]

I read that heat from exhaust and cause the rubber hubs to fail, but I do not remember what caused the excess heat on them.

maybe a problem with the cooling of the exhaust tuner?

[robert graham]

Are these new props/hubs or are they used props with rebuilt hubs?.... Maybe a rebuilt prop hub is weaker than a new prop hub?

[DennisG01]

Are these new props/hubs or are they used props with rebuilt hubs?.... Maybe a rebuilt prop hub is weaker than a new prop hub?

Good thought. However, it really makes no difference. A rebuilt rubber hub IS a new hub. Other than a defect or a shoddy job, a rebuilt prop is perfectly fine.

[Jason2tpa]

Yeah; agree w/ Dennis....hubs takes years of wear before they give and spin. Something ain’t right. And whatever it is it’s got nothing to do with the hull or engine. I’d first verify the correct hub is installed. Sounds simple enough, but there are many variations for each engine/hp/prop/prop shaft. Second is I’d contact the manufacturer of the hubs you been spinning. Verify with them you’re using the correct hub per engine/prop specs. Perhaps there was a recall on that hub. Either way, they’ll be able to provide the best troubleshooting assistance.

[DGEXPLORATION]

So, Paul informs me that he has gone through spun hubs on three props, not two. I am sorry that I can't relay all the details, since I was only fishing with him when it happened on two occasions. The three props were purchased new ( I listed details on the two I currently have in the intro), so I don't think it is a hub mismatch. The one currently running Solas has a rebuilt hub, and like I mentioned, everything is fine under 4200 rpm. In fact, Paul has not exceeded that limit for ~ 3 years for fear of spinning out, and has not spun a hub in that time period. I'm in a bit of a jam, as I don't want to push past the RPM limit, and have to pay for a hub install, or go buy an expensive new prop, if there is a real mismatch.
At first, I was a little skeptical that he wasn't just hitting stuff on the bottom, but although I mentioned oyster reefs, we mainly fish over fine sand. In my own experience, I have never spun a hub on any of my other boats, but have severely dented and busted off a few blades on timber in fresh water. These were all aluminum props, but it still seems like it should take a lot more to spin out, even if he was dredging sand most of the time.

[99yam40]

as I said earlier, over heating a rubber pressed in hub will cause it to fail.

I am guessing these were the pressed in hubs and not the ones that anyone can just slip a new on into.

higher RPM means you are burning more fuel and pushing more exhaust thru the prop.
I would start asking Yamaha techs at local dealers about what would cause this problem.

I am sure Rodbolt17 is the one I saw post something about this, but sadly he has not posted here in some time now

[Jason2tpa]

Never heard of a rebuilt hub, but ok. Why one would use rebuilt when brand new they’re under $50. The rubber ones that is. Either way, the hub is metal or rubber. Metal are machine pressed, rubber press in by hand and hammer. No way he’s spinning metal hubs because he’d go through as many props as he has hubs. And just because the props were purchased new (hubs installed) doesn’t imply the correct hub is matched for the prop shaft splines.

I find it a bit crazy your buddy keeps running his rig but won’t exceed certain rpms for fear of spinning prop. It’s a cotter pin followed by crown nut followed by washer, then the prop magically pulls off. Look at the hub splines and inspect the shaft splines. 5min job tops. I promise.

[99yam40]

not sure why you think there are metal pressed in hubs.

[DennisG01]

Never heard of a rebuilt hub, but ok. Why one would use rebuilt when brand new they’re under $50. The rubber ones that is. Either way, the hub is metal or rubber. Metal are machine pressed, rubber press in by hand and hammer. No way he’s spinning metal hubs because he’d go through as many props as he has hubs. And just because the props were purchased new (hubs installed) doesn’t imply the correct hub is matched for the prop shaft splines.

I find it a bit crazy your buddy keeps running his rig but won’t exceed certain rpms for fear of spinning prop. It’s a cotter pin followed by crown nut followed by washer, then the prop magically pulls off. Look at the hub splines and inspect the shaft splines. 5min job tops. I promise.

"Rebuilt" hub means a "new" hub. In other words, the propeller is being rebuilt with a new hub. Extremely common. In many cases it's less expensive to have a hub rebuilt rather than buy a new prop.

You can hammer a new rubber hub in? I was not aware of that - the only way I know how it's done is by being pressed in.

There are no "metal" replaceable hubs that I'm aware of. Bigger drive systems (Mercruiser Bravo 3, for example) and inboards (and probably some others) actually DO NOT have a "hub". The propeller is one, solid piece with no replaceable hub.

[Ferris11]

I found one of rodbolt's replies to a post that 99yam40 referred to about what might cause a spun hub. Below is the link to the post and one of rodbolt's replies in that thread.
https://www.yamahaoutboardparts.com/...-on-lower-unit

02-18-2016, 07:23 PM
without looking at a parts diagram,thats going to be your job.
quite a number of large V6,V8 outboards use a metal pipe between the trim tab cavity and the propshaft bearing carrier to use the trim tab scoop to supply extra cooling water to the prop hub.

and that's the issue on some Vmax engine mounted on bass boats with jack plates and surface or semi surface piercing props and low water pickups.

if your running the anti ventilation plate out of the water or the wrong or no trim tab that's what happens.
melted hubs and it wont matter if its flo torque,pressed in or cusion lock.

His following replies goes into even more detail in his own unique, insightful and sharp-witted way. Wishing him the best and hope to hear from him soon on this site.