Article reposted with permission from News From The Bow.
The old saying “fiberglass doesn’t die” is mostly true. Not so for original boat engines.
Those of us who maintain an engine(s) that propels a boat have, at one time or another, considered re-powering. Perhaps “old faithful” hasn’t been so reliable lately. Maybe the need to carry spare oil has outstripped available storage space. Has the Admiral’s tolerance for diesel smoke been exceeded? Then there’s the desire for more fuel efficiency and/or speed. For Jorgen Naess it was, to one degree or another, all of the above. “We barely made it up the river at the end of the season. Oil was leaking into the bilge. The mechanics had low confidence they could repair the engine and the marina never even mentioned a repair estimate”. Options were limited. “For just a moment we considered selling the boat, but we like her too much to do that. The other option was a new engine.”
After years of service it was time to replace "old faithful"
S/V Evangeline, a 1984 Scanmar 33, was originally powered by a Volvo 2003MD 28 HP diesel. The process of installing her new engine, a Yanmar 3 cylinder 29 HP diesel, took five weeks and was performed by Brewers Post Road in Mamaroneck, New York.
As is common when re-powering, the engine bay needed reconfiguring because the footprint of the new engine didn’t match the original. This meant relocating engine mounts. New engines generally are attached to new transmissions and require a change of prop shaft. A muffler upgrade was also performed and a new fuel filter system installed.
The result? According to Jorgen “We cruise at 7.2 knots at 3200 RPM (maximum RPM for the new engine is 3600) rather than 6.4 knots with the other engine. Although the original engine was rated at 28 horsepower it was not able near the end of its life to deliver that much power. The replacement engine weighs the same as the original, is a little quieter and runs much cleaner. The only problem is the dipstick location. The Yanmar’s dipstick is on the opposite side of the engine compared to the original and is more difficult to get to. This isn’t too high a price to pay for the final result”.
According to our panel of marina experts the total cost of replacing an engine on a typical 20-year-old boat is:
1. The cost of the engine plus
2. Approximately 1.5 x the engines cost for installation
This estimation includes relocating engine mounts and reconfiguring the engine bay, changing the prop shaft and muffler, installing a dripless stuffing box, and upgrading the fuel filter system.
The best part of S/V Evangeline’s re-powering story is it’s ending…now that they have reliable power aboard, Jorgen and Rosemary are planning an extended cruise this summer. We wish them many years of trouble-free boating.
S/V Evangeline's engines before and after:
More great articles like this can be found on News From The Bow.