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  1. #1
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    Verification of bad alternator prior replacing

    Good morning, thank you for this wonderful source of relevant knowledge everyone provides here.

    1. 1B173818
    2. 2005/Mercury/225CXL SW
    3. Mirage 19
    4. 5800 RPM
    5. StarCraft currently not finding motor (screens replaced but motor is not setup as port)
    6. StarCraft Gauges (currently non-functional)

    I have read a few different forums on Battery Load testing, Alternator input testing (red and purple wires from small clip), Alternator output testing (Alternator output) and Fusible Link Lead testing. With the resources already discussed on this form, its my understanding the Alternator is bad but would like confirmation from the community that the troubleshooting performed was correct.

    1. Battery load test, proved to be successful as expected with a brand new fully charged battery.
    a. Starting battery is brand new 1000CCA Interstate flooded battery.

    2. Tested red and purple Alternator input wires from small clip to ground, with engine running. (Clip was removed prior starting the motor )
    a. 12.76v from both leads.

    3. Tested Alternator output (directly on Alternator)
    a. 12.64v

    4. Tested from end of fusible link lead connection point
    a. 12.56v
    This connection point where power cable comes in is a bit corroded and will be cleaned once the boat is out of the water.

    From the above steps, it seems input is working as expected (red/purple clip leads). Alternator is probably shot and I have a used OEM alternator that came off a parts motor. Please confirm the troubleshooting steps preformed above and I'll plan on sending the used alternator to a repair shop to make it perfect prior installing.

    Another question, please let me know if a new thread should be started on this. Is there anyone in Long Island, NY that can be recommended to reconfigure my ECM to work with my SmartCraft gauges or is Vessel View or some other tool worth the money I could purchase to do this and other diagnostics myself?

    Thank you all in advance for your input!
    Brian
    Last edited by decojones; 07-15-2021 at 10:06 AM.

  2. Member
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    #2
    Get the alternator rebuilt.



  3. Member
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    #3
    Thank you Savage, my thoughts exactly. I will bring the used OEM alternator I have to be rebuilt.

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #4
    1B172818 is probably not your serial number, as that serial number does not even have an alternator (and is not Smartcraft Compatible).

    Only things I don't see in your testing:

    -Was the 2-wire plug reconnected prior to testing voltage at the output terminal of the alternator (engine IDLING)?

    -Did you remove the alternator ground lead, and clean it?


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  5. Member
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    #5
    You are correct sir, the serial number is 1B173818 and has been updated in the original post.

    -Was the 2-wire plug reconnected prior to testing voltage at the output terminal of the alternator (engine IDLING)?
    I did not reconnect the 2 wire plug with engine Idling but did reconnect with engine off and restarted with the same outputs.

    -Did you remove the alternator ground lead, and clean it?
    Yes ground lead was removed and cleaned along with power output from Alternator

    An update to yesterdays steps preformed.

    I brought the "used" OEM Alternator I had on hand to a shop for testing and rebuild if necessary. They tested and the alternator was working as expected. I then proceeded to replace the Alternator on the motor following the Mercury guide snippets.

    1. Disconnect Battery Cables from battery (I opted to remove from ALL batteries, even house bank since I was installing a new GPS)
    2. Disconnect wiring harness from alternator - 2-wire plug and output lead
    3. Remove belt from alternator and tensioner
    a. my belt needs replacement (Not sure if you can provide part number and I'll order thru you)
    4. Remove alternator attachment bolts and don't drop them or wrench in the canal :)

    Reinstall:
    1. Attach new alternator with attachment bolts at 40lb-ft torque.
    2. Reinstall belt to alternator and flywheel making sure groves are correctly seated.
    3. CLEAN and reconnect wiring harness output lead and reconnect 2 wire plug.
    4. Reconnect Battery cables to batteries being sure not to short them.

    After replacing the alternator I am now seeing 14.7v at alternator output and 14.1v at battery indicating it is working correctly

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #6
    Belt is Part# 828507Q11.

    Sounds like you're up and running. Keep a close eye on that alternator at higher RPM's for a bit, just to make sure you're not seeing and high or low voltage conditions at WOT.

    Often, problems that present at higher RPM's are not found on traditional automotive test equipment (specifically due to the speed limitations at which they can spin the unit to test it).

    When your engine is spinning 5500 RPM's, your alternator is singing along at approximately 16,500 RPM's.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  7. Member
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    #7
    Yikes that's fast..

    Will a voltage test from a device plugged into the motors starting battery suffice? I will keep an eye out for this later today/tomorrow if so.

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    Yes. Technically best to measure at the cranking battery, but for general purposes you can monitor any number of voltage reporting devices (Smartcraft is another great means of monitoring).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  9. Member
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    #9
    Good afternoon and meaningful Memorial Day to all.

    I'm restarting this thread since the boat is back to square 1 (let me know if a new thread should be opened.)

    Almost 2 years have gone by and up until the end of last season, there were no issues with the charging system.

    Just a few days ago, I powered up the motor and found the battery voltage stayed under 12v after idling for over 10 minutes.

    Following the same troubleshooting steps after recharging the batteries this is what the readouts are:

    1. Voltage at battery before restarting: 13.5v
    2. Voltage at battery after restarting (left to idle 4-5 minutes): 12.6v
    3.Voltage at output terminal on alternator: 12.6v
    4. shutdown motor, unplug connector on alternator, restart motor
    5. Voltage on Small red and Purple wires: 12.5v

    Any thoughts on what else could be wrong other than a second defective alternator? I replaced belt and cleaned all terminal connections on the engine side prior going down this path.

  10. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #10
    Alternator ground bad, or alternator failed.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  11. Member
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    #11
    Cleaned up all grounds for good measure and the alternator was still not pushing any juice. New alternator arrived yesterday and put her in, now I'm getting 13.8-14.1 at idle. I'll keep an eye on the voltage once the boat goes in and gets moving.

    Thank you again Don!

  12. Member lpugh's Avatar
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    #12
    Quote Originally Posted by decojones View Post
    You are correct sir, the serial number is 1B173818 and has been updated in the original post.

    -Was the 2-wire plug reconnected prior to testing voltage at the output terminal of the alternator (engine IDLING)?
    I did not reconnect the 2 wire plug with engine Idling but did reconnect with engine off and restarted with the same outputs.

    -Did you remove the alternator ground lead, and clean it?
    Yes ground lead was removed and cleaned along with power output from Alternator

    An update to yesterdays steps preformed.

    I brought the "used" OEM Alternator I had on hand to a shop for testing and rebuild if necessary. They tested and the alternator was working as expected. I then proceeded to replace the Alternator on the motor following the Mercury guide snippets.

    1. Disconnect Battery Cables from battery (I opted to remove from ALL batteries, even house bank since I was installing a new GPS)
    2. Disconnect wiring harness from alternator - 2-wire plug and output lead
    3. Remove belt from alternator and tensioner
    a. my belt needs replacement (Not sure if you can provide part number and I'll order thru you)
    4. Remove alternator attachment bolts and don't drop them or wrench in the canal :)

    Reinstall:
    1. Attach new alternator with attachment bolts at 40lb-ft torque.
    2. Reinstall belt to alternator and flywheel making sure groves are correctly seated.
    3. CLEAN and reconnect wiring harness output lead and reconnect 2 wire plug.
    4. Reconnect Battery cables to batteries being sure not to short them.

    After replacing the alternator I am now seeing 14.7v at alternator output and 14.1v at battery indicating it is working correctly
    Many rebuilders do not use OE or better replacement parts, if using a rebuilder be sure to discuss the importance of doing this, especially the rotor as the stresses on it are tremendous compared to automotive applications.
    I would place bet on the rotors are failing.!
    Last edited by lpugh; 06-05-2023 at 09:34 PM.
    Thank You Leon Pugh

  13. Member
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    #13
    ^^^^^^^ +1 dont have any around me that i would let do it
    .................................................. ...the scariest thing in life is the unknown ...................................