February 2026 Column IS YOUR BOAT A CANDIDATE FOR REPOWERING? PART 2 By Capt. John N.Raguso
Picking up where we left off in last month’s column, we posed a series of tough, honest questions that each boat owner must address before moving forward with any type of repower project. I also shared how this process works in the real world, where I had to make some challenging decisions when it was time to repower my family’s 1999 EdgeWater 185 CC. In this month’s column, we’ll bring our sterndrive brethren into the decision mix and discuss the nuances of removing and replacing a semi-permanent hunk of steel and aluminum that’s sitting in the belly of the boat down in the aft bilge area Let’s Go I/O
One of my saltwater buddies Rob Stachurski recently repowered his boat, a 1999 Boston Whaler 23 Conquest that was running an original MerCruiser 350 cubic inch MPI V8 sterndrive gasoline engine rated at 300 HP. This was connected to a MerCruiser Bravo 3 counter-rotating, dual prop outdrive. Back in September of 2025, his engine experienced a catastrophic failure (cracked block) and since he was fond of the memories made on his boat “Summer Skis”, he decided to repower it and make a few more happy times. Rob worked with the folks from C&D Marine in Copiague to remove the old engine and replace it with a new Quicksilver 350 MPI (multiport injection) 5.7L V8 engine that was a complete drop-in unit. The labor cost to remove the
original and swap it out with the replacement was $2,200. The new Mercury V8 I/O engine cost was $18,400, with the total invoice for parts and labor adding up to $20,600 plus sales tax. The 5.7L MPI Bravo Turn Key Quicksilver engine package is the perfect repower to replace a variety 5.0 EFI, 5.0L MPI, 5.7L EFI and 350 MPI sterndrive Bravo models. It’s 100% complete and ready to drop in and connect to the boat owner’s transom and existing stern- drive, backed by a 3-year MerCruiser warranty. This new 350 cubic inch V8 powerplant is rated for 300 HP @ 5000 RPM. The engine features a Quicksilver cast iron engine block and cylinder heads; raw water cooling with warm exhaust manifolds; a flush system; special flame graphics; multi - port fuel injection using Cool Fuel II; dry joint exhaust; a roller camshaft; with Engine Guardian and is SmartCraft ready; mechanical throttle and shift; and a 10 - pin connection harness. The fact that it produces its 300 sea ponies using 87-octane fuel is an added bonus. The entire process took a month, from the removal of the old engine, ordering and installing the new one, and then performing the requisite sea trials before delivery. According to Rob, the top speed with the old MerCruiser power- plant with ½ fuel (45-gallons in the Whaler’s 90-gallon tank), a light load and trimmed out was 32-mph @ wide
open throttle. Sea trials with the new engine and existing Bravo 3 outdrive hit an impressive top speed of 38-mph at WOT, which translates to a 19% improvement. With a few late season runs over to Fair Harbor in Fire Island, Rob noticed that he was using less fuel to go back and forth to his slip in Amityville. Historically at 3200 rpm, the old setup produced a cruising speed of 25-mph. With the new Quicksilver replacement engine, the same 3200 rpm throttle setting now generated 28-mph, a 12% increase in cruising speed, with the tacit understanding of improved fuel efficiency and MPG. The moral of this story is that a successful repowering of an old favorite applies to a variety of boat types, not just outboards.
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