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Thread: engine rotation

  1. #1
    1fastlx
    I am new to twin engine boats. I have recently bought a 26' wellcraft with twin 350s. The engines have been replaced and the drives have been reworked. My question is are both props supposed to turn in the same direction or has someone done something wrong? I was looking at new props and most sets I have been seeing are RH and LH. What advantage/disadvantage does the rotation have on performance and economy? The boat runs and handles well but speed suffers compared to the other boats with the same setup.

  2. #2
    1fastlx
    guess I could give more info. 81 Nova II merc 260s and gen 1 mercruiser drives. I get 50mph at 4700 rpms with 20p props.

  3. #3
    GoCiggie31
    I am new to twin engine boats. I have recently bought a 26' wellcraft with twin 350s. The engines have been replaced and the drives have been reworked. My question is are both props supposed to turn in the same direction or has someone done something wrong? I was looking at new props and most sets I have been seeing are RH and LH. What advantage/disadvantage does the rotation have on performance and economy? The boat runs and handles well but speed suffers compared to the other boats with the same setup.
    I believe the early Mercs were the pre-alpha and did not have counter rotating, so normal for that era.
    The 26 Nova's are great wave crushers for their size and are cool ol' school offshore boats.
    They have a pretty deep deadrise and are heavy boats so they will take alot of power to make it go. I have seen some 26Nova II with stock big block/alphas run in the mid 60's ++. Make sure your hull does not have a hook before you start throwing too much monies in engine upgrades.
    Check offshoreonly.com and speedwake.com for lots of info on your model.
    Best of luck and safe boating

  4. #4
    curtis73
    I agree. Unless they've been upgraded, those should be Alpha MR drives and although they offered a reverse rotation MR, most were not.

  5. #5
    1fastlx
    thanks for the replies, they are pre-alpha drives. the boat has spent its life in the water and the hull appears to be free from hook "at least with my 4 foot level" however it has been painted with anti fouling paint. It looks like "spray in bed liner" I know that has to go as it will be in fresh water while I own it. I live on a small lake in Tennessee and we have really enjoyed this boat more than any other we have owned. Do you recommend changing the port engine to ccr? I will be buying props anyways mine are in bad shape. or just keep the both in cr and buy new props?????

  6. #6
    GoCiggie31
    ..... Do you recommend changing the port engine to ccr? I will be buying props anyways mine are in bad shape. or just keep the both in cr and buy new props?????
    IMHO,
    if you are satisfied with the boat's performance now and there are no unusual engine noises with good oil pressures and the drive-oil looks clean,
    i would send out the props to Throttle-up or B-Blades and have them either fix or recommend a new set-they are great peeps and wise. This would probably be the most cost effective way and with the right prop tweeking you may pick up a few mph.
    FYI, I had a Nova as well and a bow lifting prop worked much better for me (ie:Quicksilver Lazer 21's) than the stern-lifters (i.e Hydromotive) but that was in the mid eighties and technology has changed quite a bit with prop work and labbing.
    Best of luck
    btw, the drive is what determines the rotation.

  7. #7
    Junior Member GN107's Avatar
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    Nov 2012
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    I would recomend leaving the engines in there currant rotation. Too much to change to turn one engine around. Plumbing, Mounts, bell housings, drives, props, the list goes on and on. Work with the propellers. I think that is where you will see your biggest gain.

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