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Thread: Dual Outboard Jet Motors

  1. #1

    Default Dual Outboard Jet Motors

    Has anyone ever played with mounting two outboard jet motors on a boat? I'm wondering about getting more HP in the boat and have two separate engines in case there is trouble with one of them. Are there any issues with the water being impeded into one or both of the jet units?

  2. #2
    Member Akgramps's Avatar
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    Apr 2008
    Last civilized place on the planet


    A friend of mine runs two older (way old) Merc 50's on a 20' flatbottom boat, it does quite well as far as handling and load hauling, it does not have a tunnel/s. The older 2 strokes were quite light and it seems to work for him.

    Personally I see no real big advantages, two motors will always weigh more than one and weight on the transom is always the enemy.
    Plus maintaining two is more expensive than maintaining one. If you have the boat motors sized and setup with twin OB jets and lose a motor it would be doubtful you could get on step with one, maybe if you emptied the boat......?

    His twins are making 70 at the jet/s and I bet a modern 90 would be comparable and use less fuel, a 115 yammie 4S would be 80 at the jet and weigh 415 or so, maybe heavier than his old mercs............just guessing here......but that yammie would push that old 20 and burn 4.5 gallons a hour with plenty on giddyup, I doubt those twins would burn less.....

    Just some examples, so yes it can be done, but not so practical IMO, unless you start talking much bigger boats that you cant push with one motor, then you may as well have a IB............IMHO.....
    “Nothing worth doing is easy”

  3. #3
    Member alaskabliss's Avatar
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    Jul 2008


    We had a 20' Monarch with twin 50 jets growing up. As already posted, there is twice the maintenance and almost twice the weight with two motors. We switched the two motors for one 90 and burned less fuel and had a lot better performance. Speed, fuel, maintenance and load handeling. Another problem with twin jet outboards is when turning sharp. The outside motor would start sucking air and cavitate. You had to really work the throttles but you were losing performance big time. Another problem was that two motors are not easy to syncronize. But when they were they would hum you to sleep!

  4. #4


    I have a 18' ATEC Hydro Lite with 2 older Merc 35 HP jets. Like the others have said, I don't recommend it. Cavitation on one jet unit when turning, dual maintenance, and extra weight on transom, have troubles getting on step with a single motor, etc.


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