Bearings

[Jack Kent]

I replaced the front and rear bearings last fall on my K&B 7.5 OB. After a total of approx. 4 hrs. running, I can feel that the front bearing is a little rough. Is this to be expected? Who sells the best replacement bearings? I have not replaced the PTO bearings - do they typically last longer than the front and rear?

Thanks

 

[tnrcboatracer]

Bearing life really depends on the quality of the bearing, the steel, etc; and even more so how you take care of them after running. The fuels we use are not kind to bearing steels if left alone after running. Hence the need to flush the motor properly after running, and pickling the motors in the off season.

Typically, the PTO bearings do not get the fatique pounding of the crank bearings. But I have seen a lot of them rusty over the years. Just remember that any degradation of the bearings means increased friction and that is lost HP.

As for sources, check the FS and Mfg FS forums.

 

[jetpack]

I can feel that the front bearing is a little rough. Is this to be expected?

My 3.5 SS didn't last a full season of occasional sport running on the front bearing. I suspect the front bearing is the first to go for a lot of people with these outboards. Why? For me, I think it is partially a starvation issue possibly and another could be starter pressure. I know mine took it's fair share of being blown down a lot with my starter on it.

I'm going to try a ceramic hybrid type this time with stainless races to see what happens there.

The PTO bearings are sort of difficult to tell if they are properly taken care of at the end of the day because there can be a good amount of water hiding in the lower unit. Those will be getting all stainless open bearings.

Going with a high castor mix will help with all this also as will a shot of thinned castor to the top bearing (if unsealed) when running the starter.

 

[tnrcboatracer]

I can get whatever you need for both hybrids and full SS. For the full SS, I assume you mean 440SS. I think that the 300 series balls are too soft.

 

[jetpack]

They've already been bought but thanks tn

From what I've learned about bearings your right about the stainless.

440 actually is still on the soft side for what a bearing should be, but the advantage of corrosion over chrome takes over I guess and where they are going in the motor (pto) doesn't necessarily call for a really hard bearing so I figure it would be a good choice.