Logo
Results 1 to 17 of 17
  1. #1

    Default Heat Sink & Diode

    What does the heat sink and diode do?
    Thanks
    Click image for larger version. 

Name:	Heat sink & diode .jpeg 
Views:	11 
Size:	128.9 KB 
ID:	27944

  2. #2
    Join Date
    Nov 2011
    Posts
    3,420

    Default Re: Heat Sink & Diode

    Along with the other pair, they form a full wave bridge rectifier. In plain-speak, they convert the AC alternator output to DC for charging the battery.

  3. #3

    Default Re: Heat Sink & Diode

    Yes, I see the other part on the diagram. How do. you know if they're bad and how do you test them?

  4. #4
    Join Date
    Sep 2010
    Posts
    22,789

    Default Re: Heat Sink & Diode

    Must be on a mid 1960's V-4 motor.---

  5. #5
    Join Date
    Sep 2010
    Posts
    22,789

    Default Re: Heat Sink & Diode

    Must be on a mid 1960's V-4 motor.---Is your motor not charging ?----Tested the stator windings?

  6. #6

    Default Re: Heat Sink & Diode

    It's charging but how high should the voltage range be at the battery?

  7. #7
    Join Date
    Sep 2010
    Posts
    22,789

    Default Re: Heat Sink & Diode

    Around 13.5 / 14 volts at a fast idle.----Model # of your motor ?------Those 2 diode parts are cheap.-----Might not hurt to have spares on hand.----Your location ?

  8. #8

    Default Re: Heat Sink & Diode

    Mind will jump from low 12's to 16's. Is this too high?
    It's a 1966 80hp Johnson. model V$AL-18.

  9. #9
    Join Date
    Sep 2010
    Posts
    22,789

    Default Re: Heat Sink & Diode

    Perhaps the voltage regulator is the issue.

  10. #10

    Default Re: Heat Sink & Diode

    How do I test the voltage regulator?

  11. #11
    Join Date
    Nov 2011
    Posts
    3,420

    Default Re: Heat Sink & Diode

    You know the diodes are good because it obviously is charging. Besides, that type was very durable.

    Voltage regulator: From the factory service manual: With the solid state regulator, there can be only two types of failure, under (no) charging or overcharging. Run motor at least 20 minutes to stabilize the regulator. Then with motor running 2000 RPM and all accessories off, check the voltage at the regulator red wire. If the voltage is in excess of 15 Volts, the regulator should be replaced.

  12. #12

    Default Re: Heat Sink & Diode

    Thanks for the info. If I find the regulator is bad what are your suggestions for a replacement?
    I see some nos ones on Ebay and a CDI one like the one pictured.
    Name:  CDI Regulator .jpeg
Views: 24
Size:  18.4 KB

  13. #13
    Join Date
    Nov 2011
    Posts
    3,420

    Default Re: Heat Sink & Diode

    Since it's been probably 50 years since I've had occasion to replace one, I don't have an up-to-date preference.

  14. #14

    Default Re: Heat Sink & Diode

    Thanks fdgator. I'll do some research on CDI Electronics. Maybe someone here can reply with their experiences with a CDI regulator.
    I'll let you know what I find out.

  15. #15

    Default Re: Heat Sink & Diode

    Looking at the wiring diagram the red wire runs to the ignition switch. Do I check voltage at the ignition switch?

  16. #16
    Join Date
    Nov 2011
    Posts
    3,420

    Default Re: Heat Sink & Diode

    The book is sort of confusing. In one place it says to check voltage at regulator. another place simply says "check battery voltage".
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	img151.jpg 
Views:	3 
Size:	796.2 KB 
ID:	27946  

  17. #17
    Join Date
    Nov 2011
    Posts
    3,420

    Default Re: Heat Sink & Diode

    You got me pondering on this one. Studying the system and how it works, the regulator is monitoring the voltage on the red wire as it is presented to the regulator input. Therefor, it should be measured at the regulator red wire, as instructed and shown in the picture. If it "sees" more than 15V at that location, it should cut back on alternator output. Measuring it anywhere else introduces the possibility of error due to other possible faults. Now to relax my brain awhile. Whew!

Similar Threads

  1. Ready to sink the boat
    By Junior78 in forum Identifying Model / Year / Horsepower
    Replies: 2
    Last Post: 07-29-2019, 10:57 PM
  2. Will a f115 sink me?
    By Alluvium in forum Yamaha Outboard Forum
    Replies: 2
    Last Post: 10-28-2014, 09:40 AM
  3. How does this sink work?
    By footbrake in forum Boat Plumbing Systems
    Replies: 0
    Last Post: 06-21-2013, 04:12 AM
  4. Replies: 2
    Last Post: 03-31-2011, 08:45 AM
  5. Help need with my sink
    By letsrock in forum Miscellaneous marine engine topics
    Replies: 5
    Last Post: 08-21-2008, 01:28 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
  •