MONTAUK 17 Engine Mounting Height
Posted: Sat May 26, 2018 6:00 pm
I have a 1990 Boston Whaler Montauk 17' with a 1990 Yamaha 90-HP two-stroke-power-cycle engine. When I purchased the boat the engine was mounted in the top hole [which is probably the lowest position--jimh]. Judging by the installation it might be the original mounting height and probably was used that way its entire life.
I removed the engine over the winter so I could clean it, paint it, and clean the transom. The boat was a mess and not well taken care of. Now that I have everything on the engine painted and cleaned up, I am ready to install the engine.
Today I experimented with the different [engine mounting positions or] holes to see how far off the bottom of the boat [keel] the [anti-ventilation] plate is at level trim. The third hole down from the top [this is probably what we would refer to as two-holes-up mounting--jimh] puts the [anti-ventilation] plate 2-1/4-inches higher than the bottom of the boat [keel].
The second hole down from the top [this is probably what we would refer to as one-hole up mounting--jimh] puts [the ventilation plate] at 1-inch above the [keel].
And the top hole [the lowest mounting position] puts [the anti-ventilation plate] about 3/4-inch below the [keel].
Some people have recommended [two-holes-up position].
Others have said to have the [anti-ventilation] plate no more than 1-inch from the [keel].
One person said the boat porpoised in the [two-holes up position] with the engine trimmed in all the way.
I appreciate everyone's opinion and would like to get this engine re-mounted the first time at the correct height, to avoid doing it over.
Thanks John Donovan
I removed the engine over the winter so I could clean it, paint it, and clean the transom. The boat was a mess and not well taken care of. Now that I have everything on the engine painted and cleaned up, I am ready to install the engine.
Today I experimented with the different [engine mounting positions or] holes to see how far off the bottom of the boat [keel] the [anti-ventilation] plate is at level trim. The third hole down from the top [this is probably what we would refer to as two-holes-up mounting--jimh] puts the [anti-ventilation] plate 2-1/4-inches higher than the bottom of the boat [keel].
The second hole down from the top [this is probably what we would refer to as one-hole up mounting--jimh] puts [the ventilation plate] at 1-inch above the [keel].
And the top hole [the lowest mounting position] puts [the anti-ventilation plate] about 3/4-inch below the [keel].
Some people have recommended [two-holes-up position].
Others have said to have the [anti-ventilation] plate no more than 1-inch from the [keel].
One person said the boat porpoised in the [two-holes up position] with the engine trimmed in all the way.
I appreciate everyone's opinion and would like to get this engine re-mounted the first time at the correct height, to avoid doing it over.
Thanks John Donovan