Hi Tycho... Hmmm, 2/10 of a mm is about .008" and while not as much as I had, it's getting loose. You can probably (?) get away with running it for awhile yet. Just how long is anybodys guess though. Is that the crank pin (while trying to rotate the crank) or the whole shaft (counterweight included) moving up and down? "Radial" play is what I'm talking about, in the bearings. The loosness between the balls and the inner/outer races.
I had a 10x7 prop on my Evo before I re-built it, and after running it, while still hot I could move the prop fore and aft probably an 1/8" at the tip, so my bearings (rear especially) were REALLY bad...I however had the attitude that if it blew up I wasn't gonna bum out about it, and just let 'er rip. It got to the point however that I just couldn't stand the noise any longer.
Does the shaft spin smoothly, or is there sort of a "grunchy" feeling/noise when you spin the crank?
I went to a local bearing supplier and got both bearings for $16.50 + tax and did 'em mysef in less than an hour.