I have installed a couple of the sei alpha replacements and so far so good. However, when I bought my 3 liter 225 efi merc a couple of years ago, I was told it had a new merc lower on it. After about 2 or 3 hours of run time the prop shaft broke. When I dropped the lower to fix it I saw that is was an sei unit. Yes they did repair the lower but I was stuck paying for a $700 prop that I had borrowed to test on my boat. They only offered to sell me a so las prop at a discount

I put one on a Yamaha outboard. Fit and worked well. Until i ran it into a large pile of rocks after about 10 hours of use...LOL. They rebuilt it under the no questions asked warranty. Also sent a failure analysis back with the repaired unit, IMPACT DAMAGE. I would definitely use one again.

I dont , just run them the season and change it when you winterize it . The impellers are really soft .