Rev 4 to something else

[QBhoy]

Merc makes two types of flow torq hubs, rubber and stainless
https://www.quicksilver-products.com/en/marine/marine-propellers/marine-propellers-hub-kits

Here is a mirage with solid hub 13243
https://www.ebay.com/itm/154394947462?hash=item23f2a7ef86:g:hSEAAOSwZKRgYlYA

There are a few flo torq kits. They are all of a composite brittle plastic type make up, as far as I know. Certainly the sacrificial part itself.
There was one released not too long ago that deals with heavy props. Has a little give when shifting.
Makes a huge difference, I thought.

 

[alldodge]

I contacted Merc support a few days ago and they said stainless. They recommend rubber for their motors 300 and less HP. Stainless 350 and up

Also said I could run solid

 

[dingbat]

I contacted Merc support a few days ago and they said stainless.

Interesting…stainless on stainless is infamous for gulling. Goes against all engineering norms. Wait and see how that works out for them in the long run.

Solid hubs shouldn’t be a problem if you have a good prop shop. Sent my 4 blade (Evinrude Offshore Renegade) out for balancing and polishing every other year. Came back with a new hub the last time out. Since relegated to spare duty since installing the Enertia

 

[alldodge]

B3 is S on S but also gets pulled every year to grease spline

 

[QBhoy]

I contacted Merc support a few days ago and they said stainless. They recommend rubber for their motors 300 and less HP. Stainless 350 and up

Also said I could run solid

Ah. Didn’t know this was a thing AD. Do they not mean the actual splined receiver insert is stainless ? The sacrificial bit itself surely still of the usual brittle polymer (of some sort) material? Think I’ve seen the drive splined insert in different materials. Like a phosphor bronze almost and others apart and of another alloy perhaps. Can’t quite remember the name of the version of the flo torq I was given by the dealer I know a while back. But it’s of the type that is designed for large diameter blades big boy props. Without it, my mercury 2016 outboard and its big CT gearbox, made a bit of a clatter on occasion when going into gear with the big bladed tempest plus on her. Most noticeable of all was the rattle off her when at idle in gear and going down the river where I moor. With the current running with me, there was a hell of a rattle off her…that was with just the normal flo torq hub kit for up to 300/400hp or what ever it is. Then getting that newer one…what a difference. Night and day how smooth it is now. Never really noticed it with the x7 allow stainless enertia prop though. Being so lightweight.
On that note..been really looking into those enertia eco props, with your boat in mind. I think they sound ideal for you. Not cheap though. But if they are available in the one inch increments that the normal enertia is…very useful thing for being able to get it just right. They will be much cheaper for you over there, than they are for me here, I’m sure.
There is, from memory, two types of enertia eco. The most recent of which, is the eco XP. Designed for lifting heavy hulls and astonishing mid range efficiency when cruising. Worth looking into AD
I’m likely annoying the life from you with this by now…but really think you’d be doing your lovely boat and her equally lovely motors a disservice, should you throw on a pair of very blah and outdated prop design on her shafts. I’d be going modern technology, preferably of the X7 material, all day long.

 

[Stinnett21]

I suspect the stainless hub is for a high horsepower racing setup. If you have enough money to go racing you're not worried about saving internal parts you're worried about spinning a prop in competition.