I was at an estate auction this past weekend, I went because they advertised a bunch of woodworking tools and fishing gear.
There was a 90's era Mercury 115 on a pallet, it looked okay but the auctioneer said its condition was unknown and that it was found 'out back' in one of the outbuildings laying on its side covered in a tarp. The cover was off, three spark plugs were broken off, and the power tilt was fully extended. The flywheel turned and made a complete revolution with what seemed to be decent compression. I wasn't interested since I didn't need that size motor for anything, but when it came up for bid, they started the bidding at $1500, but got no takers, then someone jumped in at $200. In seconds it was already up to $2000, and it sold for $2,750. There was no way to check compression, there was no way to start it, and the power tilt unit was likely stuck in the up position, plus there were a few missing parts, some rotten wires, and the thing had obviously been sitting neglected for a long time as there were vines growing through the steering bracket and around the prop, as if it had spent a long time outdoors on the ground at some point.
In my mind, that tells me it was a motor someone gave up on. Something went wrong that made them retire it. That could have been as simple as the tilt motor going bad, or it could well be something far more serious. There's no way I'd take a $2,750 gamble like that.
With all that in mind, there was a 1996 Mercury 90hp on FB listed for $4499, it was only up for a couple of days before it was marked sold and soon after removed. That motor was listed as not having run in 10 years and with compression readings ranging from 75 to 143 psi.
I think what's going on is that people who had bought four strokes are starting to realize that they're expensive to repair and maintain when they get old. They seem to be seeking out the older tried and true 2 stroke motors.
On a smaller scale, a few months ago I picked up a second 14ft aluminum boat, which came with a running 15hp Johnson on it. I bought the boat because its the exact same hull as one of my boats here and I wanted to set one up for running the upper river here. My original boat has a very typical 9.9hp Mercury four stroke from 1999 on it. It runs good, and I've owned it since new. It starts easy, is pretty easy to work on, and it gets me there. But its slow, it will not get a 14ft boat and me on plane, its a 7 mph rig at best.
I took the 15hp two stroke boat out this morning, it started in three pulls, everything is as I found it, (the guy was using it when I found it).
While I know this is comparing a 15hp to a 9.9hp, the difference is beyond night and day. The 15hp, moves that 14ft Starcraft along at just over 21 mph on the gps and gets it on plane almost instantly. The 15hp is lighter, faster, and starts almost as easy. Its not as quiet, and not as good on gas. It burned roughly double the fuel that the 9.9hp 4 stroke motor burned in the same distance. I've had 9.9 and 15hp OMC motors before, the difference between the two is basically just top speed, with the 9.9 pulling a bit harder down low than the 15hp. I figured I'd be topping out at about 18 or 19 mph if it were a 9.9 vs. a 15hp.
When I got home, I pulled the 15hp off that boat and hung a mid 80's 35hp Evinrude I had here, which will be its permanent motor.
I have a guy coming for the 15hp tomorrow for $1,500 cash.
I picked up a 9.9hp Honda, a 2004 model tonight off CL for $200, its got good compression, but the guy tried to rebuild the carb himself and screwed it up. I never had a newer Honda but I ordered a new carb and linkage online for it as well as a new water pump and some spare spark plugs.
