TWC

There are different Mercury Flo-Torq hub kits for different props, we all know that. But I have a specific question about the difference between the hub kit for a Mirage Plus and a Revolution 4.

For the hub kit for the Mirage Plus (and most other Mercury props) is 835257K 1

The hub kit for the Revolution 4 is 835257K 6

These kits are identical EXCEPT for the addition of one part in the Rev 4's kit. That part number is 23-856163Q 1 and it is called "Bushing - Prop Hub"

This additional bushing is used in the kits for the Tempest Plus, Trophy Plus and the Rev 4.

I presume it helps support these heavier props, but my real question is: What would be wrong with using this bushing with a Mirage Plus. If it helps keep the prop centered and supported on the prop shaft, why does Mercury distribute two different kits with two different part numbers.

What would happen if you did NOT use the bushing on a Rev 4?

Ed

Is the Mirage thrust washer too large of an outside diameter, thus restricting exhaust flow? I have two(2) new, in the box, part # 845257A1 hub kits available, if you need them. Depending on where your located...$30.00 each shipped. Thanks, Ed

bbladesprops

Until about 3 years ago, all the props you mentioned came with the A1, K1, Q1 kit super session but all the same). Some of the performance OB applications like go-fast Bass boats who surfaced their propellers, began to experience wobble and prop loosening. The first thought was to change the entire insert/sleeve. It became more cost effective to make a separate piece and use it in conjunction. The bushing and the sleeve have gone through a few running changes as the years went on. We actually made a slightly longer bushing to use in ET's and chopper props for those who wanted the security of delrin in the deeper bore propellers. Mirage props didn't fall into this usage group because they ran submirsed most of the time, and the multitude of hubs in kit form work just fine. If a person was going to run high power with a mirage (300-400 hp), they should go to the solid hub anyway. Using the K6 kit is fine with any shallow depth borepropeller. Running a Rev 4 without the bushing will probably not hurt anything. That prop got grouped with the rest because of a few instances. I think you may see the K1, Q1's gone and all going to K6 in the future. Hub kit issues can get confusing. The thing to remember is that your thrust washer, hub, and washer package all mate together so no movement is evident. Remember, 55 ft/lbs. on the nut.

TWC

Thanks for that information Brett.

You said the sleeves have one through a few running changes. I have three drive sleeves with the same part numbers. Two of them are smoothly tapered in the forward end, the other sort of steps down as it goes deeper which is how the bushing is designed.

Which is the newer design?

Ed, the thrust washer is the same with either kit or Mirage Plus & Rev 4.

bbladesprops

TWC,

The stepped version is the newest version.