Results 1 to 8 of 8
  1. #1
    Join Date
    Mar 2015
    Posts
    1,033

    Default Yanmar 3GM30 rev counter temperamental

    Sometimes it works, more often it doesn’t. Obviously a new one is going to be surreally expensive, and I can happily live without it, but are there any checks I can do to find the cause?

  2. #2
    Join Date
    Mar 2015
    Posts
    1,033

    Default Re: Yanmar 3GM30 rev counter temperamental

    Did a YBW search on this and found nothing. Have since done a google search and it came up with loads of threads on here re this subject, so ignore this one folks and I’ll work through all the suggestions on aforementioned threads.

    Why is the forum search function so awful, by the way?

  3. #3
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    22,133

    Default Re: Yanmar 3GM30 rev counter temperamental

    Intermittent faults are notoriously difficult to trace but I would start with checking all wiring and connections.
    Answers to some technical queries at new website http://coxeng.co.uk

  4. #4
    Join Date
    May 2018
    Posts
    800

    Default Re: Yanmar 3GM30 rev counter temperamental


  5. #5
    Join Date
    May 2001
    Location
    UK East Coast
    Posts
    37,241

    Default Re: Yanmar 3GM30 rev counter temperamental

    Quote Originally Posted by fredrussell View Post

    Why is the forum search function so awful, by the way?
    Like a lot of this site, it's badly programmed by people who presumably never have to use it. If you want to search the forums, do it via Google by prefacing your search term with site:ybw.com/forums

  6. #6
    Join Date
    Aug 2004
    Location
    Cumbria; U.K.
    Posts
    3,319

    Default Re: Yanmar 3GM30 rev counter temperamental

    The usual sensor on GM engines is an inductive type located on the top of the bellhousing. It screws into a tapped hole. You could start your wiring check there.
    Also, the sensor counts starter ring-gear teeth and the gap between the teeth and the sensor is fairly critical, slightly too big and the tacho stops working. Can't remember for certain, but the workshop manual might have details to check.

  7. #7
    Join Date
    Jun 2007
    Location
    Colchester, boat Tollesbury
    Posts
    1,058

    Default Re: Yanmar 3GM30 rev counter temperamental

    If the sensor is the same as the one fitted to the Yanmar 3JH30A (probable) I had the same problem. The sensor on the bell housing has 2 push fit crimp connectors (automotive type) . The wire ends from the loom were corroded and stripping back to good copper then extending the leads back to new clean crimps has resolved my issue, I spent a little time with emery cloth on the actual sensor connections, and a wipe down with vaseline to keep them dry. Has worked faultlessly since.

    Ian
    Tollesbury.

  8. #8
    Join Date
    May 2018
    Posts
    800

    Default Re: Yanmar 3GM30 rev counter temperamental

    There are no end of after-market rev counters available for almost nuppence, some of which could no doubt be incorporated into your Yanmar panel.
    It isn't rocket science!

Bookmarks

Posting Permissions

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

Latest YBW News

Find Boats For Sale

to
to