Last April I bought a used '99 model Mercury 25hp outboard from a Mercury dealer that hasn't been in town for very long (2 or 3 years). The owner told me that the engine had locked up and he had a brand new powerhead put on it. He told me that it came with a 90 day warranty from Mercury and that I had to break it in properly (25:1 gas/oil mix, and adjusting speeds throughout the first tank of gas). I've had some trouble getting it started lately. The guy told me that you have to "prime" the choke (by pulling the knob in and out about 5 times) instead of pulling it out and leaving it until it is started. This method doesn't work very well. However, I did pull it out and leave it until it started the other day and this seemed to work well (which way is it supposed to be?). O.K., now for the good stuff; I talked to another Mercury dealer in town (which just happened to be the dealer that sold the motor to it's original owner) about my dissatisfaction with this motor, and they looked up the serial number on Mercury's warranty computer. They told me that they had put TWO different powerheads on this motor while it was under warranty!!! That would make this the third powerhead to be on my motor. My question is, should I be concerned that this powerhead will blow too. And, what would cause a motor to lock up powerheads like that, could there be something else wrong with the motor that causes damage to the powerhead? Should I get rid of the motor before it happens again? There is a river nearby where there are boat garages/storages on the river and the duck hunters leave their boats in the water year round. There is a lot of scum, mineral deposit, or something like that caked on the shaft of the motor (mostly around where the waterline would be). By the way it is a Model # 25EH, 1999, Serial #OG930797. The originating dealer said that a new powerhead costs around $1800 so it doesn't make sense for the dealer that I bought it from to sell it for $1600 with a BRAND NEW stainless steel prop. The warranty info didn't show that Mercury had helped in buying the third powerhead. Thanks to anyone for their comments and oponions. I can't decide what I need to do!!!