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
   
Get instant online access to repair manuals for your Mercury / Mariner outboard. Online Manuals
MercuryMariner
Order printed Mercury / Mariner service manuals — shipped to your door! Printed Manuals
MercuryMariner
Use engine diagrams to find & order parts for your Mercury / Mariner engine. Engine Diagrams
MercuryMariner
Find parts quickly with Mercury application guides. Quick Parts Guide
MercurySierraCDI
Results 1 to 8 of 8
  1. #1
    RBaron's Avatar
    RBaron Guest

    Default My 1972 mercury 20hp is not ge

    My 1972 mercury 20hp is not getting fire. Kill switch O.K.Am getting voltage to coils from stator. Points making and breaking. Coils not firing????

  2. #2
    Join Date
    May 2007
    Location
    Inverary, Ontario, Canada - The Great White North Eh!
    Posts
    8,455

    Default "This has a Thunderbolt II ign

    "This has a Thunderbolt II ignition, so there should be a "capacitor" integral to your stator.

    The high or low speed windings power is rectified and stored. When the points "close" the capacitor should release it's charge to the coils.

    How do you know you have voltage to your coils?

    They don't decide whether or not to fire.

    Once the charge is released/triggered by the points, the power is passed from the capacitor through the coil to the plug - nothing there to switch or stop it unless it is grounding out before it gets to the coil....

    If the coils are getting power, then either, both coils are shot, they are grounded out, both plug wires are bad, or the plugs are both bad.

    The odds of "both of anything" simultaneously going is kinda remote..."
    Graham

    A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

  3. #3
    RBaron's Avatar
    RBaron Guest

    Default Wire coming from stator to coi

    Wire coming from stator to coils show's voltage when I turn moter over but I don't know any values. I checked the coils with ohm meter and they checked the same. Unlikely that they would both be bad and check the same?? Do you know what I should get out of stator? A/C or D/C Thank you for you'r help!!!!! Ron

  4. #4
    Join Date
    May 2007
    Location
    Inverary, Ontario, Canada - The Great White North Eh!
    Posts
    8,455

    Default "Sorry, I don't have a fac

    "Sorry, I don't have a factory manual for this far back. But can tell you that the leads going to the coils should be DC.

    The stator produces AC but it's rectified to DC and stored in the Capacitor. The points then release it to the Coils.

    In the slightly "newer" ignition systems the voltage being fed to the coils is usually in the 200-300 volt range, the coils then upconvert to about 35,000 - 40,000 volts.

    Sorry, can't even really say if your ignition should/would be in that range, but would suspect something similar...."
    Graham

    A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

  5. #5
    Join Date
    May 2007
    Location
    Inverary, Ontario, Canada - The Great White North Eh!
    Posts
    8,455

    Default "Sorry, I just found a note in

    "Sorry, I just found a note in my pile of "yet to be filed" - the capacitor on your system sends approx 1000 volts DC to the coils...."
    Graham

    A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

  6. #6
    Charles Scott's Avatar
    Charles Scott Guest

    Default My 25 hp Mariner will not fire

    My 25 hp Mariner will not fire on either cylinder. I've replaced the switch box and rectifier but still no fire. It's a stick stear/remote start. Any ideas as what to check for voltage at the stator/trigger/alternator leads?

  7. #7
    Join Date
    May 2007
    Location
    Inverary, Ontario, Canada - The Great White North Eh!
    Posts
    8,455

    Default "Charles, do you have a serial

    "Charles, do you have a serial number for the motor - it will help with specs..."
    Graham

    A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

  8. #8
    Join Date
    Oct 2007
    Location
    Winnsboro, Louisiana, Franklin
    Posts
    9

    Default "Graham, I believe I've s

    "Graham,
    I believe I've solved my problem. The trigger coil showed to be opened on my ohm meter. My repair manual says it should have a reading of 750 to 1400 ohm. I pulled the coil out of the housing and sure enough the top several hundred windings were burnt. I've got a new one on order and I should be back to pestering the Crapie and Catfish by next Wensday or so.
    P.S. The manual shows DVA of 4V+ on the trigger coil and 180V+ on the charging coil. I'll verify this when I get everthing put back together.
    In the mean time, keep up the good work on the board and I'll try to pitch in and help out if'en I can."

Similar Threads

  1. 1969 merc 200 20hp phelon flywheel magneto no fire
    By mountaindweller in forum Mercury Mariner Outboard Forum
    Replies: 1
    Last Post: 11-03-2010, 10:05 PM
  2. Help me with my mercury 20hp
    By jonny canuck in forum Mercury Mariner Outboard Forum
    Replies: 30
    Last Post: 07-23-2010, 06:12 PM
  3. Johnson Owners Manual 1972 20hp
    By pedal in forum Johnson Evinrude Outboard Forum
    Replies: 2
    Last Post: 06-13-2010, 11:04 PM
  4. 1972 20hp partsprop
    By jhall555 in forum Chrysler Force Outboard Forum
    Replies: 2
    Last Post: 04-27-2009, 02:41 PM
  5. 1972 merc 200 20hp
    By casey Moore in forum Mercury Mariner Outboard Archive
    Replies: 0
    Last Post: 06-13-2008, 10:53 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
  •