Proper Bearing Choice for K/B Outboards

[david brooks]

I am replacing the stock bearings in my 3.5 SS Outboard. All four of them. Two engine bearings and two PTO bearings.

The stock replacements are unshielded chrome bearings with plastic retainers if I am not mistaken. Corrosion was the primary reason for the replacement besides the front engine bearing which was just badly worn.

I am thinking of going with stainless steel bearings with a full contact rubber seal, or at the very least - removable stainless shields so they can at least be dis-assembled and re-greased.

:?: My question is this...which bearing faces to keep left open? Either type of bearing seal can be removed from one side, or both. The seal has little effect on cost between the two.

The front bearing traditionally is changed out to having one seal facing the outside of the case. This motor does not do a good job on pumping oil to its front bearing, even though the crankshaft is grooved for it. It gets too much water and vibration, and its a small bearing to start with. A good quality rubber sealed bearing here seems obvious.

The rear bearing does not need to be left an open style retainer for air/fuel flow, but standard practice is keeping this one fully open. What is the sucess rate of going with a rubber sealed bearing here? Is it even advised?

The Power Take Off (PTO) bearings will drink lots of water due to them being submerged at rest with most hull setups, and the lower casting halves/assembly by itself is not easily flushed. It is safe to say these two bearings live in water all their life, and and in my opinion never get the proper lubrication when they do get run. Its left up to crankcase gasses to do the job (weak against water) and the bottom bearing never does see oil due to the casting web between them sealing it up.

:arrow: Should I just keep the contact seals on each outer race of the engine/ pto assembly and rely on the fuel mix inside the engine to keep them all happy?

:arrow: Keep each one fully sealed and hope water never enters them and unknowingly break down the grease pack?

:arrow: What would be a maintenance routine for the option if any, like just removing the powerhead at the end of the day to spray out the bearings, ect.

This particular motor involves careful thought on waterproofing and corrosion as it is a stack of four bearings and simple "blowing out with after-run oil" at the end of the day or before storage does not agree. The assembly traps too much water and you cannot be assured it is all removed.

What would be your best line of thinking when it comes to choosing bearings and pampering them for this motor?

Does anyone else run seal setups like im talking about in thier K&B Outboard?

I'll post the bearing sizes for my 3.5 SS for reference here:

(2) 8 x 22 x 7 Power Take Off Bearings
(1) 13 x 24 x 6 Rear Engine Bearing
(1) .250 x .625 x .196 Front Engine Bearing