Logo
Results 1 to 9 of 9
  1. #1

    Default Wiring problems Model 620 4 cyl Positive Ground

    New to the forum:

    I'm not sure the ammeter is wired correctly. I have the generator wire and the key switch wire on one side and all others on the other side. I have a brand new Napa 6 volt battery. Ammeter shows charging when running but the battery totally discharged 24 hours after use. No lights, bilge pump or ignition left on. Seem to have an electrical leak somewhere. How do I test? Is there an easier solution other than disconnecting the battery after each use?

    hbr95404

  2. #2
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    6,826

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    The generator's output should be on one side of the ammeter...the key's wire should be with "all others"...if you want the ammeter to show the "whole story".

    whether wired as is or as suggested above, it still doesn't explain the discharge in a day...the easiest way to test is to isolate one circuit at a time until the discharge current stops...that's the circuit with the 'leak'. a clamp on ammeter is the best tool but they aren't cheap for DC circuits...

    Welcome to ME.com

  3. #3

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    Many thanks for the rapid reply. Another question: I'm assuming that the model 620 is positive ground based on the diagrams in the handbook I ordered of the ME site. But they are not specific for the 620 4 cyl. The motor was removed from a Lyman and I don't have any info on how it was grounded. If I'm wrong, that would explain the rapid discharge? I did polarize the generator after installing the battery as a pos ground system. The water pump is powered off the generator shaft and there is a voltage regulator on top of the generator if that helps with identification. I'm pretty much electrical illiterate so any advice and information would be appreciated.

  4. #4
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    6,826

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    I'm pretty sure the starter wont work right if the polarity is "backwards".

    If you have the manual, that's probably the best info available...unless somebody has converted something.

    As far as the rapid discharge, I'd get an ammeter and find the source...sometimes, you have to disconnect one wire at a time to find the "offending" component...

  5. #5

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    I have a model 620 in an old 1955 Lyman and am wrestling with polarity issues also. Mine came negative ground, but I think that it was switched sometime ago from originally being positive ground. The starter works correctly either way, but I cannot get the temp sending unit to work negatively grounded. I would be glad to send you photos of any wiring areas that might be of help to you. Also, do you have fresh water cooling? I am trying to set up a FWC system but unsure about the sizes or capacities of the various components. I would be very interested to know the details of any system that has proven to be successful.

  6. #6
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,191

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    Any consideration for changing all of this out to a standard 12 volt system?
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  7. #7

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    Not really. Everything is all 6 volt - the original instrumentation, starter, generator, bulbs, etc. and would very much like to keep it this way. Also I have no need/ or desire for modern gadgets that would only be 12 v.

  8. #8
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,191

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    Quote Originally Posted by gmillikensr View Post
    Not really. Everything is all 6 volt - the original instrumentation, starter, generator, bulbs, etc. and would very much like to keep it this way. Also I have no need/ or desire for modern gadgets that would only be 12 v.
    Actually, I was addressing my question to the OP here.


    As for your no need or desire for modern gadgets ....... are you still sailing with Columbus and Magellan?

    Seriously.... what are doing for a modern day FF, DS, GPS or VHF radio?


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  9. #9

    Default Re: Wiring problems Model 620 4 cyl Positive Ground

    Sorry for the delay in posting. The boat is at our summer home, 2000 miles away right now, so I'll quit worrying about it over the winter. I plan to have an old motor electrician look at it next summer and am seriously thinking about switching to 12 volt system. I have a vintage 12 v instrument panel which will make it easier. The boat is a 1938 Penn Yan. There is a fresh water cooling system. I'll be glad to send photos next spring if you will contact me then.

Similar Threads

  1. 1977 mercury 850 positive ground?
    By adamandtater in forum Mercury Mariner Outboard Forum
    Replies: 8
    Last Post: 06-29-2013, 07:44 PM
  2. positive to negative ground
    By scouser4 in forum Boat Electrical Systems
    Replies: 1
    Last Post: 10-25-2012, 07:42 AM
  3. Battery/ground wiring question.
    By captain_ed in forum Boat Electrical Systems
    Replies: 3
    Last Post: 10-30-2011, 09:24 AM
  4. Positive or negative ground
    By badger5301 in forum Mercruiser Sterndrive Archive
    Replies: 5
    Last Post: 05-08-2009, 05:01 PM
  5. Positive ground
    By jim81961 in forum OMC Sterndrive and Inboard Archive
    Replies: 2
    Last Post: 02-04-2009, 10:34 PM

Posting Permissions

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