Outboard Engine prop shaft bearings

[C08]

My 20 HP outboard main engine has only 7 seasons use and as an auxillary engine on a sailing cat has done only 350 hours mostly at moderate speeds. There is noticable play in the prop shaft but no water in the gear oil and the gears etc are pristine fortunately. On the shaft is a ball race behind the reverse gear and a needle roller bearing at the prop end of the shaft. To my mind either the needle race or the ball bearing is worn and should be replaced, not an expensive job for me to do. It has been suggested to me that I should just leave it as the bearing play might be within the new spec anyway. That does not sound like good advice to me as I cannot believe that the oil seal (lip type) is designed to cope with a shaft wobbling about and that fairly quickly will start to leak and let water into the gearbox or lose oil or both, with bad consequences for the gearbox.
So my question is would you expect an oil seal to fail with substantial play in the shaft and would a new engine spec have a play toleance when new anyway?
I alway raise the outboard leg when sailing and replace the gear oil each season. I wish I had a dial gauge but the play is easily felt.

 

[jim.howes]

H i, I would change the the roller race/needle bearing as neither bearings were ever really designed to have any play in them albeit certain types (tapered needle bearings) are adjustable to take up any slack which occurs with wear over time and lip seals again were never designed to run eccentrically, and like you say if the cost is low what can you lose.
Jim