Avast!!I have a 1988 Force 125 on a 19 foot flats boat I bought two weeks ago.I did the usual changing of the L/U oil and pulled the impeller also.It was cavitated pretty badly and I was happy to see a much better water circulation when we buttoned it back up and put ears on it.The next day though I went to warm it up and it wouldn't pump a drop of water.When we pulled the L/U again the impeller had been torn to shreds.Turns out they had given me an impeller for a newer model(post Mercruiser buy-out)125 and the doggone thing was 2000's of an inch larger in the shaft sleeve than the other one.We miked it out at the parts store today.It was such a hair different that we really didn't remark on it in the heat of the first job,and at the parts store I had peeked at the catalog and there was nothing else on the page that remotely resembled the part I needed bedsides the one I got.What a major pain in the butt!Why in the heck would they have made something so darn close but of course a mile away in machine spec terms?Beats me how it worked one day and went to the ****ens the next day. Hope I didn't burn the damn thing up while I was staring at it waiting for the water to start pumping out(like it had done so well just the day before).The heat alarm went off and I did shut it down right away.Hope thats not too late.Anyway... you old salts have any comments I would love to hear'em,and anyone new to the game beware of this little detail.If that impeller ain't working your whole mess is shot.I'm at yohimbo@juno.com if anyone wants to write and swap boat stories.