For 2004, 2005 and 2006, my desire to run four-strokes shifted me over to Suzuki DF225s, since these 55-degree 3.6-liter blocks were the only outboards that would fit on the Phoenix’s transom. At 600 pounds each, there would be an additional 182 pounds of net weight on the transom over the previous Mercs, and this was going to pose a real challenge. Once again the waterline had to be adjusted and the remaining two batteries migrated from aft to forward in an effort to reclaim the vessel’s original center of gravity. The cockpit scuppers were still at least 3 inches above the waterline, so I was good to go there, but while the trio of engine-well scuppers seemed OK in the bay, offshore was a different story, so I was compelled to add a trio of one-way rubber flaps over the outside of each scupper hole in an attempt to control the backflow of water into the outboard well. But the added weight aft made the transom a bit slower to recover when drifting in a following sea, and water would wash over the top of the transom and into the well, especially with three or four anglers standing in the back of the cockpit. Fuel economy for that 14-hour canyon trip was acceptable at 145 gallons (yes, the DI Mercs did get better fuel economy) and cruising speed was the same at 27 knots, albeit requiring me to push the four-strokes 300 rpm harder than the two-strokes to achieve it (4,300 rpm for the Suzukis versus 4,000 revs for the Mercs).
So what did I learn from all of this real-world experimentation? Upgrading to newer engines improved reliability, performance, speed and fuel economy as predicted. But the added weight of different types of fresh power also caused some center-of-gravity changes that adversely affected my boat’s self-bailing abilities until I was able to identify the problem areas and make the necessary adjustments to fix it. The Phoenix’s open layout and removable cockpit sole hatches allowed me to mix and match onboard components to address the weight issues. Yours may not allow this type of flexibility, so be advised.
For a chart of repowering options, click here.