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  1. #1
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    Trigger test question

    This weekend my motor (2002 200hp carbe SW 0T566776) started bogging down, at first with a little time would get on plane but did seem to be running rough. After the first day it wouldn’t get on plane at all. It would bog after throttling up and a few times it would sorta just loose all power and go back to idle while trying to plane. It ran at idle and fast idle 1200-1300 rpms all day, and ran fine at those rpms. I know need to check a lot of things such as compression, fuel delivery and spark, which I will soon but my first thought was stator. So I tested stator ohms and continuity test, all was in spec, ohms at 418. Don’t have a DVA yet but will and test more then. Then I tested the trigger, looks like a bad trigger.

    Trigger test
    Purple-Blue 684 ohms
    White-Red 605 ohms
    Yellow-Brown 769 ohms

    Way below the 1100-1400 ohm spec.

    Edit: today I checked the timing, definitely not good. Timing on the #1 cylinder would show 4 degrees ATDC then it would show it not on the tape at all, it seemed to be bouncing around, then go back to 4 ATDC.

    So I assume time to replace the trigger?
    Last edited by leonreno; 05-31-2022 at 08:06 PM.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    Looks like the trigger is where you should start. Make sure those readings were taken with the wires DISCONNECTED.


    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).
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  3. Member
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    #3
    Yes, disconnected all the connectors near the plug, all the connectors from the control module and stator, 4 total including the trigger connector.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #4
    Time for a trigger then.


    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
    Got the DVA and test harness. Also tested compression all between 112-121.

    Ran the DVA stator and trigger output first:
    All CDMs tested very low Stator output at 0.8 Volts at cranking.

    all tested CDMs tested ok on trigger output except #6 all were right around .25 volts except #6 was .18 volts

    Then I ran resistance/diode test on each CDM
    Numbers 1,3,4,5,6 all tested good and near the same readings.

    the resistance readings were all around 50k ohms give or take 5000 ohms on the above CDMs where there was continuity.

    #2 CDM tested continuity correctly except the resistance readings were about 8000 ohms instead of the others at 45-57k ohms. And for both diode test the readings were in the 8k range. Is that a bad reading? ran the test again today and it was the same as the others around 45-55k ohms

    All the CDM trigger input resistance tests were in spec.

    All the CDM Secondary impedance test were ok EXCEPT #3, it was around 110,000 ohms. Figure it’s bad. Tried to remove wire by screwing it off to check it, that didn’t work, the wire ripped off, I think. Not sure how they screw off. â€â€‹Screwed the cable back on today and retested the resistance and it was back to within spec.

    Stator resistance test still within spec.

    Trigger resistance test still low, around 600-700 ohms.

    what should my next step be?

    Should I replace the cdm where the trigger input was below spec at .18 volts, or is that more about a bad trigger than a bad CDM? Should I buy two and swap them out to see if one regains correct stator output?

    I know I need a new trigger.

    The stator I’m not sure about, not sure if a bad CDM could be making the faulty stator test. Was going to test at 2500 rpms but then I tore the plug wire off, figured that wouldn’t be good.

    The service manual says that if stator output is low but resistance test are ok, then says to replace the CDMs one at a time with a good CDM until output returns to normal. So seems like if one or two of my CDMs are bad then they could cause the output problem.

    Also read on the CDI troubleshooting page, that you can test the stator output disconnected from the CDMs, is this ok to do? It says if reading stays low, stator is the problem, if reading goes to normal, CDMs are the problem. How do you test the stator leads? Positive lead on one of the connectors and negative on a motor ground? Or is it just DVA connection between the two wires on the connector, between green/white and white/green. â€â€‹Ran the test today, I unplugged the stator connector and tested between the two terminals, got a reading of 220v on the DVA at cranking speed.

    Thanks for the help, wish my issue was a carburetor, or something simple.
    Last edited by leonreno; 06-12-2022 at 08:09 PM.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #6
    Sounds like you need a #2 CDM and a Trigger. Then retest.


    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
    Quote Originally Posted by EuropeanAM View Post
    Sounds like you need a #2 CDM and a Trigger. Then retest.
    That was my thought, may buy a second CDM so I can test the others in case I have a second bad one. I’ll be placing the order on your site soon.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  8. Member
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    #8
    Don, Ordered my trigger and two CDMs from your website so hope to test them soon. In the meantime I have a question, the manual says to swap out a CDM at a time and see if the test return to normal. I get that. BUT, can I in the meantime disconnect all CDMs and hook up one CDM and test, if results are good then add one more CDM and test, and keep adding a CDM doing this and see if connecting one CDM causes the problem. Or could there be a problem testing them this way at cranking? Would having one or more disconnected skew the results, mainly the stator DVA output with the test harness. Also, when I run these test, I run them with the plugs out and the plug boot grounded with alligator clips, not with a spark gap tester, would having the spark gap tester connected and the spark actually crossing a gap effect the results?
    Last edited by leonreno; 06-17-2022 at 03:31 PM.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  9. Member
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    #9
    Ok, I’m the idiot. I have one spark gap tester so I decide to test the spark gap on the cylinders, but I was getting no spark at all. Got in the boat to check the kill switch, it was fine, then I saw the key switch and thought to myself, does the switch need to be in run for spark? And how about the DVA stator test? Switched it to run, as I have been using a trigger switch connected to the solenoid to turn the motor over. Well what do you know, that makes a huge difference. First, all plugs jumped a 7/16” gap and then I retested the stator and trigger outputs, all CDMs had between 220-270 volts output and the trigger output came up to between 0.55 - 0.85 volts. So seems the stator is ok, and trigger output is in spec, still lowish but resistance is still half. So hopefully the new trigger and a new CDM will do the trick.

    2nd update today: tested trigger/stator output at idle and revved up to close to 2000 rpm (I know, not great but only way I can do it without traveling 40 minutes.). At idles stator output was around 290 volts and trigger output around .8-1 volt. When I revved it up, only did It twice on two CDMs, trigger output went down to around .5 volts instead of up to 2-8 volts. So hopefully new trigger is the thing, will remove it soon and check the magnets also.
    Last edited by leonreno; 06-17-2022 at 06:25 PM.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  10. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #10
    Sounds like you're on the right track.

    Can't unplug all of the CDM's as three of them are the "return ground patch" for the other three.

    Once you understand how that works, it's possible to remove multiple CDM's as long as there's still a return ground path present.


    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
    I received the trigger and 2 CDMs last week. Today I had time to just remove the flywheel, stator and trigger. After removing the trigger and flywheel I noticed some rub marks on the flywheel hub magnet and the trigger as well. The rubbing is light and on the magnet you can’t actually feel anything, on the trigger, you can see a feel where it rubbed. Looks like on one of the trigger points. Again not real bad, is this anything I should worry about as I am swapping triggers. This could of happened 20 years ago when it was started for the first time or recently.

    second question, one of the five stator screws snapped off in the motor, I believe I still have a few threads that will hold. How important is it to try and remove the broken screw and use a new screw or just tighten down the one I have with loctite. Such a small screw looks like it will be super hard to remove.

    pictures of trigger an magnet

    AEACB576-E498-4CF6-9C7D-98BC6F9340B5.jpeg

    AF9F866E-AD31-4788-BC91-52F3BDB66436.jpeg
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  12. Member
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    #12
    #1 possible heat build up in that trigger pole not worried seen it many times , # 2 uh oh 4 should hold fine if you cnt remove it, id try, i replaced a end cap on one one time without block teardown
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #13
    Thanks joe, thought probably 4 should be fine, think it’s best to leave out broken one as it would be bad if it came loose in the motor. Another question, when I was trying to remove the flywheel I was struggling with it and turning the flywheel back and forth a little, there was a light clinking type noise coming from the motor as the pistons turned, is this normal? The spark plugs were still in the motor. Sounded like the rings maybe, maybe from compression moving them, hopefully?
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

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    #14
    how much back , water pump may be damaged , clink hard to tell from here
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #15
    Just about 10-20 degrees, not much turning. Going to replace water pump anyway.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

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    #16
    Quick update:
    I stalled new trigger and the timing is consistent at 2* ATDC with no jumping around, still have to replace two of the CDMs and then do a link n sync, maybe tonight.

    have two questions:

    1. is there a specific idle timing I should be shooting for when I do the link n sync, says 0-8* and before this all happened it was set at at 4*, is there a consensus on the best timing for idle?

    2. I have the timing tape to test all the cylinders, haven’t installed it yet, figured I do the timing on cylinder 1 first then add it. My question is that it has only three timing places, so how does that work with the six cylinders? Do I have the wrong tape or do they overlap, I thought each cylinder fires each revolution so it seems I should have six timing spots on the tape.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  17. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #17
    Technically you have 3 triggering points in the trigger.

    I would set the idle timing at 4 ATDC as your starting point.


    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

  18. Member
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    #18
    I installed the new trigger and two new CDMs. The idle is steady on all six cylinders now, trigger voltage at idle is up to around .9 volts. I did link n sync and got the numbers right on idle 4* ATDC and cranking WOT at 24* BTDC. I ran it at idle in my tank and it seems the idle is speed is lower than before and when I throttle it up in neutral and bring it back to the “forward idle stop” the idle stays elevated compared to when pulling the throttle all the way back to idle. Don’t know why that is, idle stop screw is set just as described in the manual with the paper test. One other thing that concerns me is I had to screw in the idle advance screw a good bit to get it to 4* at idle even though it was at 4* before I changed trigger. Before adjustment it was right around 0*. I plan to put it in the water and readjust when in gear so maybe it will change back some then.

    one other thing, the throttle barrel retainer is broken at the top latch so it stays up when I move it up but don’t think it will stay up, I think it’s been that way for awhile just never noticed. It looks like to replace it the whole throttle plate/arm thing has to be replaced, am I right? Might try a zip tie around it hold it.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

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    #19
    98889 is latch part number , was link arm measurement correct , does it have an idle module on it ????? is timming comming back when arm is returned to idle position ?????
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #20
    Thanks Joe, I didn’t think to check idle at the two different spots, I’ll do that soon. Link arm measurement was correct. It’s a 2002 so it has the stock boxes, can’t be removed.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

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