Logo
Click for Nissan Tohatsu Manuals, and Parts!
Results 1 to 8 of 8
  1. #1

    Default NS3.5A vibration shaking the whole boat

    I have an old NS3.5A on an American 18' sailboat.
    It seems to have a lot of vibration that it didn't used
    to have. Shakes the bracket and the whole boat.
    Changing the throttle setting doesn't seem to help.

    Motor starts and runs well....plenty of horsepower.

    Could one of the magnets on the flywheel be shifted?
    Or, something else?

  2. #2
    Join Date
    Mar 2010
    Location
    Buffalo, NY, USA
    Posts
    2,056

    Default Re: NS3.5A vibration shaking the whole boat

    If the flywheel magnet came loose, the motor would be severely off time, so that's doubtful, since it runs well. More likely the bracket tilt bolt and/or "distance piece" that separates the two halves of the transom bracket need to be snugged. I would put a piece of carpet, or better yet, rubber, between the boat bracket and the motor bracket. Also be sure that the boat bracket is snug.
    Paul
    Buffalo NY USA

  3. #3
    Join Date
    Aug 2017
    Location
    South Africa
    Posts
    95

    Default Re: NS3.5A vibration shaking the whole boat

    Is your prop still in good condition?

  4. #4

    Default Re: NS3.5A vibration shaking the whole boat

    I thought about that. There are no chunks taken out, or other damage to the propeller.
    Although, it is well worn. Also, the vibration does not seem to depend on the RPM of
    the engine. You would think that there would be a resonance point...but, no.

  5. #5

    Default Re: NS3.5A vibration shaking the whole boat

    I found that the swivel bracket "A" is quite loose on the stern bracket bolt
    as compared with another engine that has seen much less use.
    I rarely open the throttle more than one-third. I tried opening up
    more than two-thirds and it does smooth out. Time to replace
    some parts.....

  6. #6
    Join Date
    Aug 2017
    Location
    South Africa
    Posts
    95

    Default Re: NS3.5A vibration shaking the whole boat

    I was going to say to check the brackets next, Tohatsu unfortunately have very soft engine mounts and bracket bolts, this was the first thing we had to change out when I still raced Tohatsu .... Yamaha engine bolts are very strong, we raced those on the standerd ones ...

  7. #7
    Join Date
    Mar 2010
    Location
    Buffalo, NY, USA
    Posts
    2,056

    Default Re: NS3.5A vibration shaking the whole boat

    Tighten the bolt that attaches the swivel bracket to the transom clamp brackets.
    Paul
    Buffalo NY USA

  8. #8

    Default Re: NS3.5A vibration shaking the whole boat

    Yup...I tightened the nut on the tilt bolt.
    Seems much better!

Similar Threads

  1. shaking bad once warm
    By bubbas in forum Yamaha Outboard Forum
    Replies: 4
    Last Post: 08-28-2017, 10:56 AM
  2. bravo 3 shaking back of boat up to 1000rpms
    By obxfhb in forum Mercruiser Sterndrive Forum
    Replies: 4
    Last Post: 02-01-2012, 07:47 AM
  3. Boat vibration
    By draven620 in forum Mercruiser Sterndrive Archive
    Replies: 9
    Last Post: 06-16-2009, 05:11 PM
  4. Shaking
    By redsnapper386 in forum Mercruiser Sterndrive Archive
    Replies: 7
    Last Post: 05-11-2009, 11:53 AM
  5. Need help shaking down new setup
    By skeetermatt in forum Mercury Mariner Outboard Archive
    Replies: 7
    Last Post: 11-07-2008, 10:05 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •