MarineEngine.com - Your online store for all types of marine engines and boat parts.
PHONE ORDERS
Monday - Friday
9:00 AM - 5:00 PM EST
Click for TOLL-FREE Number
Online Checkout
Special $9.95 Flat Rate Shipping
(800) 209-9624 | Home | Contact | Shipping | Returns | Cart View your shopping cart.
Part Number Search
Shop by engine/drive part number.
Original & matching parts for sale.
Manuals & Accessories
Shop by description, item number
or manufacturer's model number.
Boat Repair Forum Boat Repair Forum   Boat Video Gallery Video Gallery
   
Results 1 to 6 of 6
  1. #1

    Default Mercruiser Stern Drive noise

    I recently replaced my Mercrusier Alpha1 Stern Drive with a genuine new Mercruiser unit.
    It seems to run fine but there is a kind of harmonic humming noise at cruise speed, 3000-3500rpm.
    I broke the unit in as per mechanics guidelines and have replaced the break-in oil. I have put about 40 hours on it since replacement. Gimble Bearing was checked and is in good shape. I am using a Merc aluminum 16x16 prop which has some cavitation burn marks on it but is otherwise in good shape. I did not have this noise with my original leg. Any ideas what may be causing this and if I should be concerned?

  2. #2
    Join Date
    Aug 2006
    Location
    Calgary, Alberta, Canada
    Posts
    2,426

    Default Re: Mercruiser Stern Drive noise

    I would sure check the drive oil level, as well as check it for water and metal shavings ASAP.
    It also sounds like it could be gimbal bearing or U joints as well.
    Have you greased the gimbal bearing lately?
    Was the alignment checked?

    Rod

  3. #3

    Default Re: Mercruiser Stern Drive noise

    Yes the drive oil level is checked regularly. I find that it needs a few ml's of oil to top up every 5 to 10 hrs.
    There was no evidence of water in oil when it was changed at 20 hrs and only minor shavings as might be expected from break-in (OK'd by boat mechanic) but I will check again.
    The gimble brg was checked, including alignment, and was determined to be OK when the unit was installed and was greased when the oil was changed.

  4. #4
    Join Date
    Aug 2006
    Location
    Calgary, Alberta, Canada
    Posts
    2,426

    Default Re: Mercruiser Stern Drive noise

    Some props seem to make a characteristic purring sound, but if you have not changed props, that can't be it.
    I don't have any other ideas.
    Any chance it's coming from some other area, like the front of the engine?

    Rod

  5. #5

    Default Re: Mercruiser Stern Drive noise

    I have to wait till I put the boat in the water again and get cruising to check. Thanks very much for your suggestions.

  6. #6
    Join Date
    Mar 2008
    Location
    Manalapan, nj, usa
    Posts
    3,727

    Default Re: Mercruiser Stern Drive noise

    I am not discounting your concerns regarding the humming you hear.

    But i never not heard a humming from a alpha drive.

    The upper bearing under the top cap hums. The gears turning hums also.

    Maybe you just didn't pay attention before.

Similar Threads

  1. Need some info on a Mercruiser Stern Drive
    By ken7237 in forum Mercruiser Sterndrive Forum
    Replies: 4
    Last Post: 08-19-2011, 11:31 PM
  2. Mercruiser Stern Drive Vibrations
    By nautica40383ream.net in forum Mercruiser Sterndrive Forum
    Replies: 6
    Last Post: 06-28-2010, 03:48 PM
  3. Noisy Mercruiser Stern Drive
    By oxonthebox in forum Mercruiser Sterndrive Forum
    Replies: 1
    Last Post: 06-21-2010, 04:20 AM
  4. Mercruiser 5.0L w/ alpha one stern drive
    By ghostrider_four in forum Mercruiser Sterndrive Forum
    Replies: 3
    Last Post: 05-31-2010, 09:45 PM
  5. Mercruiser Stern Drive Swap
    By tobyj in forum Mercruiser Sterndrive Archive
    Replies: 4
    Last Post: 10-18-2008, 10:33 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
  •