Advice needed - What else can seem like a spun prop hub?

[z00m]

When driving my boat, the low speed handling up to 7 or 8 knots was working fine. When I try to go up to the plane the load makes the stbd drive slip. Boat is a 1991 30' bayliner with twin 5.0 L/X with alpha 1 gen 2 drives.

I was thinking I had a damaged prop hub so went about removing the prop. The hub doesn't seem that bad when looking at it. The prop on the other hand looks terrible. My questions are:

Can a hub still spin if it looks ok? All splines look good, and the rubber to prop surface looks good. There was a shiny surface between the thrust washer and the hub. The prop was not very tight but I thought the splines did the work?

If it is the engine coupler, can a coupler give drive at low speeds and slip when loaded for getting on the plane?

Can the prop cavitate when in poor condition? The exhaust bellows was also split so can exhaust and bad prop = enough cavitation to act like a spun hub?

 

[MikDee]

It could be the prop or the coupler, looking at the condition of that prop, it's hard to tell?

 

[Eric 3.7LX Alpha 1]

Pictures have not been working on here. Instead of using the "camera" tab to the left.... instead... Clicking on the "A" tab to the right, then "image" tab which is 3rd from the right, seems to work better to upload pictures.

Try a different prop on it and see if the issue remains. You can also put a mark on the center hub and the outer on the prop and see if the marks still align after the issue. Sometimes they can still look good and be separated enough to cause trouble.

 

[MikDee]

I can see the pix if I click on the links.

 

[achris]

That hub has not spun, but the labyrinth seal area is so badly corroded that it will be allowing excess exhaust gas passed that the prop will be spinning in gas, not water. And the symptoms you have are exactly what would happen. That prop is way past serviceable...

 

[matth121]

wow, that is a rough looking prop. looks like you need a new prop and for sure a new set of anodes to protect it. what does the other prop look like? if it's anywhere close to this one- you need 2.

 

[z00m]

Thanks for the replies, and thanks Chris for confirming what I thought might be the prop losing gasses before the blades. The transom area of the boat is in general disrepair so trying to get some used transoms and drives. The eventual goal is to get it back together all serviceable, new anodes and some bottom paint. After that hopefully some 4 blade alpha 4 props. I like to cruise and don't run around at full throttle.

 

[Bt Doctur]

you really are kidding us, right? that prop was bad 10 years ago. Also you might have a bad electrolsys issue too.

 

[alldodge]

With the prop looking that bad I can guess the outdrive might be in worst shape