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Mack Boring, the New Jersey distributor for Yanmar
recently repowered a vintage Bertram 20, better known as the Moppie. Originally it
was powered by a 175-hp OMC gas engine with sterndrive. Boring replaced the 746-lb.
gas sterndrive package with a 683-lb. 6BY220Z diesel driving through a MerCruiser
Bravo III. Mack Boring sent us his test results recently and the results were so
startling that we asked to test the boat ourselves. In the meantime, we’re so excited
by the tremendous improvement in fuel efficiency obtained by the Yanmar 220-hp diesel
that we are passing them along.

A vintage Bertram
Moppie after being repowered with a Yanmar diesel goes
10 mph faster and gets over 118% more mpg. |

Mack’s Moppie being
wrung out along the New Jersey coast this spring. |

Testing was done by Mack Boring’s staff. |

Note how the rehab
makes this very old boat look like new. |

The diesel engine
actually takes up less space that the old gas engine. |