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Following up with some subjective observations regarding the new engine, and specifically in comparison to the previous engine, a 1989 2-stroke Yamaha 130 HP:

At 350 lbs, the Yamaha was light, powerful and agile. The boat performed like a sports car with near instantaneous on-plane and was quick through the RPMs to a surprisingly high WOT of 44.5-45.7 on a couple runs recorded and published back in 2006. My two splash well drains were right at the water line, with waves washing in and out in any sea state. It was a great engine for this hull.

At 470 lbs, the Mercury is quite a bit heavier, dropping the stern an estimated 1" such that the splash well drains are below water always, and the well is generally awash. Static trim remains quite pleasing, not the absolute flat sitting-on-the-chines horizontal that the light Yamaha yielded, but a mildly aggressive and slightly bow up poise. Not at all unnatural or discomforting or "bow high" as some vessels appears when rigged with twins or larger 4-strokes. The single battery remains in the splash well.

As noted in the initial post, the Mercury is powerful and exceptionally quiet in comparison. Instantaneous on plane and faster than necessary through the RPM range. One of the more amazing qualities is the acceleration that remains from any position on the throttle; throw it down from 35 or 40 MPH, and it absolutely jumps to a higher speed at a rapid pace tossing one back onto the RPS. Perhaps the large displacement is the reason for this.

The boat performs somewhat differently now, I like to think thats its gone from a sporty roadster to a powerful sport sedan. It does noticeably better in a larger seaway, busting through waves with greater ease and less motion with the additional 120 lbs on the transom. No surprise that more mass equates to less action felt from the waves.

With a loaded boat, one could sense the Yamaha working harder and yielding less. This is far less apparent with the Mercury, the boat can readily run up to 47-48 with 3 men, 3/4 fuel and fishing gear, maybe even a bimini top up, but I don't recall, it comes on and off dependent upon the mission. Load affects this engine far less than the previous. And it sings a powerful deep and throaty sound at speed, while the captain can still maintain a conversation with passengers. The sound quality improvement is truly magnificent.

As previously stated, the Mercury can hold a steady plane in small seas at 2200 RPM and 16+ MPH. With waves at a foot or two, that figure bumps up to about 18 MPH. The Yamaha held steady plane at 16 MPH, maybe it could squeak down to 15 if pressed.

Cruising speed with the Mercury is comfortable in a wide range, from 3000 RPM / 25 MPH up to 4000 / 35 MPH is an excellent range. If one has a long distance to cover and can tolerate the wind, the engine loves to cruise at 40 MPH even, but if you can't tuck behind the console or helm, a 40 MPH wind on the face is never too comfortable. The Yamaha, on the other hand, had a narrower cruising band from 22-30 MPH or so, with 25 MPH as optimal. At that speed, the engine noise was less pleasing than the wind.

Regarding engine mounting height and prop selection, I'm quite comfortable with the initial selection of the 14.25 x 19 Stiletto Advantage II recommended by Tom W. Clark. It trolls fine, if not slow enough for walleye or salmon, mid-range cruising is excellent and WOT is outrageous.

Only once have I had a problem staying hooked up with the water, in 4'-6' seas with regular 8-10 footers rolling through the Strawberry Channel off Fish Creek in Door County, WI. I went out to sport around solo, knowing seas were huge, and at the speeds necessary to keep the hull somewhat in the water, I would occasionally break free, or ventilate, heading up the bigger hills and needed to back off the throttle to reconnect the prop to water. In typical boating conditions including some large seas (not 8+'), I've not seen this condition repeat itself.

One mild irritant is the single cylinder trim/tilt system. I've established that it is either unable or unwilling to operate UP at speeds over 45 MPH or so. I'm assuming that its simply not powerful enough to overcome the thrust at that pace, as I can't imagine any sort of electronic override is preventing further trim. This only affects me on WOT speed runs, wherein I need to attempt to find optimal trim at a lower speed before kicking in the last 600 RPM or so. Ideally, to find WOT and max MPH, one can work the trim UP until blow-out, then tuck it back in slightly until it catches. I'm unable to do this.

Finally, at WOT, this boat with the higher engine mounting height is up and way out of the water. It gets super light, and absolutely seems to floating around particularly in the nose, but including a slight back and forth rocking on the vee at the stern I assume. Floating, barely under control would be a fine description, its really something completely different than WOT on the previous Yamaha.

For the record, my throttle is hitting the console at my reported top speed and WOT. While I don't believe she's got anything left, I intend to poke around in the binnacle and at the engine this offseason to see if I can correct this and verify.

Any questions? Fire away.