I won't disagree with Mercury's mid range 4 strokes. They seem to be old-school tech, haven't changed a whole lot since they hit the scenes in the late 90's and early 2000's. Many of the small changes that were made were done to improve reliability (gaskets, etc). I've been doing some home-based outboard stuff and a large majority of what I am seeing is merc and OMC & BRP. Rarely do I see a Yamaha.
Parts are available for all of them if you look around.
Used parts for Yamaha's aren't quite as popular because people generally fix them rather than scrapping them AND they don't break that often. In the 24 years I've done dealer work (yamaha and briefly Mariner/Mercury), I've only had 2 motor failures-both due to lack of oil (one was an oil change who forgot to put oil back in and the other a rat ate into a transfer tank line and the tank ran out of oil). An insurance job or two and a ton of carburetor cleanings from sitting up for months on end. These are mostly sub 100hp, most of them 25hp. While I had mercury, they were in all the time for something or other. Broken linkages, dead switchboxes, stators, wiring (the insulation would crumble on the 40 mag that I remember), coils, leaking exhaust cover gaskets, defective nicasil and then mercosil blocks, etc. And of course Merc didn't want to stand behind the warranty. The 25's were well known for exhaust cover gaskets leaking, water would get into the cylinders through the leaking cover, and would take out the #2 cylinder...rendering the block junk (it is not repairable).Obvious defects, they'd kick them back saying "not defective"-and then we'd have to call the customer & tell them they'd have to pay for the repairs since Merc denied it. A block was around $1100 back then + labor and gaskets (not much off from replacing the entire motor with a new one). Makes us and the manufacture look like idiots. Glad we got rid of them but miss having enough work to justify being a dealer. We could physically call the tech line, get approval for the repairs, then when it came time to get paid, they'd back up on it. A few of those and we were done with 'em. THANK GOODNESS. Nowadays it's all web/computer based. Maybe stuff has changed and I certainly hope so.
Having dealt with Merc/Mariner and then Yamaha factory dealer support, I can tell you first hand that from day one and day "last" (merc), Yamaha's tech support line is top notch professionals. We are a multi-line dealer of all sorts of stuff and I guarantee you that Yamaha's tech is STILL far and away the most professional of all 9 lines of products we handle. That doesn't mean that there isn't room to improve, however (there always is), but comparing to the other 8? HUGE difference! Now if we could just recruit some other outboard techs....that is a challenge across the board...nobody wants to get dirty anymore and everyone expects a million dollar annual salary for punching a program into a black box.
