Quote Originally Posted by sangerdan View Post
This is way outside my expertise. but I've seen a hole in the strut supposedly to let water into the barrel. When you are sitting still the barrel should fill except for trapped air; even if nothing was forced in by forward motion is there enough of a low pressure area at the prop end of the barrel to suck the water out? If so probably not enough to suck a vacuum so it would have to pull water in from somewhere. How much water is needed to do the job? I'll bet all the motions going on in that area are violent enough to make sure fire knowledge if water is flowing through the strut bushing the way we'd like to think impossible.
I personally believe, after putting the collar on it have little effect on bushing life, that it is NOT the pressure in front the feeds the bushing, but the negative behind the strut sucking water in. I don't see the benefit of the little hole in the set screw type collar Hotwater mentioned. I really don't see the need for a hole in the strut.
It takes very little water in the strut bushing to keep it happy. Some people swear it creates a hydraulic wedge like a main bearing. That's pure BS, because the length wise grooves in the strut won't allow a wedge to form.

I have had to run the boat in gear on the trailer before, and just let a garden hose stream on the shaft at the strut, and it was fine. Ran it for 10 15 minutes, no problem. Do it with out the hose, and you lose the bushing in a minute or less. If I had to bet on a magnaflow impellor or a strut bushing without water, I'd bet on the magnaflow out lasting the bushing.