I must be wrong?

Discussion in 'Outboard Maintenance' started by HighSide25, Feb 10, 2010.

  1. HighSide25

    HighSide25 Well-Known Member

    Ive always wanted to add a battery charging system to my 03 merc 25. it doesnt have a starter, its just your typical, short shaft, 2 stroke, 25hp merc. man tilt, man start.

    i could care less bout pull starting it.

    im curious if this is the only thing i need to charge battery?

    any idea if the "kit" is missing something?


    any other options?

    i dont mind payin the $70 for a chrging kit.
  2. Gramps

    Gramps Living & Dying in 3/4 Time

    I think you're going to need more.  Let me take a look at my motor tonight and give you a better idea.

    But for now I'll suggest:

    855721A4 STATOR ASSEMBLY $108.68
    813715A2 LEAD CABLE SET, High Tension (5 and 8.25 Inch) $17.08
    88439A28 BATTERY CABLE, Black $16.67
    88439A27 BATTERY CABLE, Red $16.67
    816770T RECTIFIER $36.38 (Part of the "Charging Kit" above)

    All of the prices from Boats.net my personal favorite for Genuine Mercury Parts

  3. Brett

    Brett > PRO STAFF <


    No heavy battery cables needed if there is no electric starter
  4. HighSide25

    HighSide25 Well-Known Member


    doesnt the motor already have a stator?

    i saw those options on rainboat. not sure if they will work for a 25hp motor 2 stroke

    so i guess the "rectifier" is the actual mechanism that grabs electric current from the motor, and trnsfers it to a battery in dc?
  5. Brett

    Brett > PRO STAFF <

    Stator plate is under the flywheel
    it's the mounting plate for the coils that produce the electric current
    that powers the spark plug capacitor discharge ignition.
    I think this kit is for your Merc


    I'd be typing for a week so...

  6. noeettica

    noeettica Well-Known Member

    Nice thing is that on two yamaha motors that I own they already have a "charging coil" Which will put out Unregulated AC .

    You then Install a rectifier to make DC
    there are many types of rectifiers available ... half wave , full wave , doublers and triplers ...But we usually run a full wave bridge ... There are however some Nifty rectifiers with built in Regulators ...

    I have a motor that I purchased from a forum member and it came with all the charging stuff ...

    A Solar panel may be cheaper ... and it workes when the motor is off :)
  7. Gramps

    Gramps Living &amp; Dying in 3/4 Time

    Ah I did not realize they already had a stator...

    Then yes, one of those kits from Rainboat should do it! You may have to pull the fly wheel to connect the wires, I would call a mechanic and pick their brain. 

    Make sure and take pictures of the project!

    Dave if you use a solar charger there are a few items to keep in mind;

    - If it puts out 50 watts or more it should have a voltage regulation system.
    - Smaller panels should have an on/off switch, if the panel is not charging the battery connected to the unit, the battery could actually discharge through the panel.

    These are just a few items from "The 12 Volt Bible for Boats" by Miner Brotheron.  I picked this book up over Christmas and it was a great read for air travel.

    P.S. - Sorry for the hijcak.
  8. noeettica

    noeettica Well-Known Member

    posted that before opening brett's link ...LOL

    It's all good Scott

    I will try to take a photo of an old Mercury Vacuum Tube rectifier and post it here ...;-)
  9. HighSide25

    HighSide25 Well-Known Member

    solar panel takes up space that i dont want to waste. they are not as clean looking as two power lines coming out of the motor(along with the tiny tach line)

    ill make some calls to mercury this week and get the verdict straight from the mouth. ill also call rainboats.

    hoping this works!
    Frank, you ever had tried something like this?
  10. Brett

    Brett > PRO STAFF <

    The hardest part of the project is removing the pull start and flywheel.
    The rest is a basic parts installation and wire routing.
  11. HighSide25

    HighSide25 Well-Known Member

    brett, ive removed many a pull starters before, and, unfurtunatly, had a mechanic replace the stator on this motor back in july of this year.... im sure he had to remove the flywheel for that.

    that said, it shouldnt be to much of a pita to remove due to it was recently "loosend"..... any special tools needed?
  12. Gramps

    Gramps Living &amp; Dying in 3/4 Time

    Only special tool I can find is a fly wheel puller http://www.repairmanual.com/catalog/DS-B-201. Other than that it seems pretty straight forward. As I'm sure you know, be careful with Mercury bolts! It seems they have a habit of snapping off in the block.
  13. HighSide25

    HighSide25 Well-Known Member

    no kidding.
    i dont want to go through that headache again
    ill have to run the motor for 5-10 minutes to get it warm, spray pb blaster, let set for an hour or so, heat it up again, spray some more pb blaster THEN super carefully undo any bolts that are in precrious positions
  14. Frank_Sebastian

    Frank_Sebastian Well-Known Member

    Kyle I would use the part number for the kit and search for a better picture of the parts. The numbers in the drawing are the parts listed (i.e. # 5 is the rectifier). I would call and ask if your flywheel will work as not all of them have the magnets installed.

    The parts shown may be all that you need. The charge circuit is going to put out maybe 12 amps so it can be small.

    Best regards,
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