possible spun prop/hub

frosh coach

frosh coach

Member
Apr 20, 2011
237
Long Island Sound, New Haven CT
Boat Info
1997 300 DA,
1994 300 DA (SOLD)
1989 230 (SOLD)
Engines
Twin Mercruiser 350 FWC, 300 HP MPI V-drives
On my 94 sundancer 300 (twin alpha gen II), I was running when all of the sudden the starboard engine started climbing up in RPM's. I pulled both back to neutral and started off slow again. The starboard would run fine until about 1200 rpm, and then the rpm's would slowly start climbing without me pushing the throttle.

I think I spun a hub? thoughts? The props are stainless, and original to the boat (1994).

the temp and oil pressure are all fine.

Thanks!!
 
Assuming you didn't have the drive trimmed up way too high to where it would ventilate, or there wasn't anything caught on the drive/prop (weeds, etc)... The next logical choice is the hub or the coupler. What type of hub does your prop have? Rubber or the plastic insert style? Assuming rubber, make a locater mark on the rubber hub and the propeller. If the hub is shot, the mark will move after you do a test run and the RPM's spin up. If it stays put... unfortunately the next logical culprit is the coupler... and the engine needs to be removed for that.

FYI, at 25 years old, the coupler has certainly seen better days. When is the last time the props have been reconditioned?
 
Wow had the same thing happen to me a few months ago.

After a good inspection the next day finding a cracked cavitation plate indicating I hit something during my travels.... I took it out to try to replicate the issue and surprisingly the engine/outdrive functioned normally and hasn't given me any trouble since.

Hope your boat heals itself. :)
 
Lazy Daze said:
Assuming you didn't have the drive trimmed up way too high to where it would ventilate, or there wasn't anything caught on the drive/prop (weeds, etc)... The next logical choice is the hub or the coupler. What type of hub does your prop have? Rubber or the plastic insert style? Assuming rubber, make a locater mark on the rubber hub and the propeller. If the hub is shot, the mark will move after you do a test run and the RPM's spin up. If it stays put... unfortunately the next logical culprit is the coupler... and the engine needs to be removed for that.

FYI, at 25 years old, the coupler has certainly seen better days. When is the last time the props have been reconditioned?
Click to expand...


The drive was trimmed all the way down. I did trim it up to ensure nothing was caught, then lowered it. I'll have the boat pulled this weekend and the hub. Do Stainless props even have a rubber/plastic hub?
 
Yes. Whether aluminum or stainless, they have hubs. Bravo III props are a different beast and they do not have replaceable hubs.
 
If the hub is the problem:
No need to pull the boat out of the water to pull the props off the Alpha drives if you don’t want to. It can be done pretty easily in the water by either hanging off of the platform and raising the drive or going to some shallow water you can stand in, anchor, raise the drive, and remove the prop and hub assembly.
Swap out the hub kit in the prop, reinstall, and you’re on your way.
Hopefully the last guy who put it all together put a lot of marine grease on the hub kit before inserting it in the prop.
If you weren’t the last guy then may be better to do it at your dock from the swim platform just in case you have to work at getting the old hub separated from the prop once it’s off of the boat.
Make sure to make note of the direction of the tapered thrust washer behind the prop and reinstall the same way, use lots of marine grease on the new hub and on the shaft on the drive to make future removal easy, and catch at least three tabs of the locking washer in the prop castle nut when reinstalling.
I usually use my cordless impact gun with an impact socket to take the prop nut off and put it back on. Just be sure to rinse the socket well with fresh water when you’re done if you do the same. The impact gun itself shouldn’t touch the water because the prop castle nut will be exposed when you raise the drive.
I do it with the drive in neutral and just hold on tight to one of the prop blades.
Once you bend the locking tabs out of the way with a flat blade screwdriver and light hammer taps it takes about a second and a half to get the prop off.
Same going back on.
If you don’t have a cordless impact and socket then you can get a plastic floating wrench to remove the nut with at just about any marine store.
Using the wrench might increase removal time to a minute or so.
 
Last edited:
The boat will be pulled tomorrow at noon. Good part about a small working mans marina... the haul is only 25 bucks. The parts guy at our marina has a hub in stock and will have it there for me. Fingers crossed!!!
 
25 bucks to haul a 30’ boat? I may have to move to Connecticut.
 
Update - the boat is out, but the mcgard locking nut is on tight. I have it soaking with kroll oil. The key was slipping when I turned it, and I didn't want to round off the teeth.

Has anyone ever cut one off? I saw on youtube that they can be cut with a die grinder. another option is to jam a screw drive between the collar and nut, then turn the collar with a plyer or vice grip.

last (stupid) question. This is the normal rotation drive. I'm assuming that you turn it left to loosen.

Chris
 
Gotta love a working yard where they let you do your own stuff.
Yes, the prop nut is like others. Lefty loosey-righty tighty.
Hope the prop lock comes off for you and you don’t have to resort to cutting it off. You don’t want to nick the threads on the shaft.
If you don’t trailer the boat, I would consider tossing that lock once you get it off.
I never used them
When I had stainless props on my old 300 I just took them off when the boat came out of the water so they wouldn’t take a walk over the winter and then I popped them back on again just before the boat got splashed in the Spring.
Didn’t need to lock the props in the water. Never had a rash of people jumping in the water to steal props around here.
Removing them for the winter also gave me a good chance to bring them home over the winter, inspect, take the hubs apart, clean everything up, grease, and put the hubs back in nice clean props.
 
So after 24 hours of letting the lock sit with kroll oil, I put the key into the lock. the tabs were line dup and I tapped the lock to secure it in place since every time we tried to turn it with a socket and ratchet it kept popping up. Well that key actually broke.

I've decided to get metal cut off wheels for the Dremel and cut the damn thing off.
 
I've never used one but looking at the pictures does the outer ring of lock spin? If not can you use something like a extractor on it? Hammer it on and go to town?

I've fought enough locking lugs and that's my go method.
 
If the lock is keyed then you should be able to drill out the keyway and the lock will act like it has been opened with a key, that is how regular locks act with that procedure.
 
I wanted to update everyone. I ended up grinding the mcgard lock with a Dremel, 20 cut off wheel and 3 hours later. I drove the prop to Hale Props who replaced the original hub (1994) and had the prop back to me in 3 days. Their exact words... " the hub was destroyed".
 
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