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Results 1 to 16 of 16
  1. #1

    Default Electrical issue has me scratching my head

    Hello All! I have a 1999 Sea Rayer jet boat that'd got some electric gremlins, I'm trying to trouble shoot but getting mixed results. The motor is a Mercury "175xr2" on a jet pump. I guess its basically the same carbureted 6 cyl of the 200 horse power outboard of the same era. Anyway hopefully I can get some help here.

    The last time I had it out I was on the way in running about 2000 rpm it bogged down like it sucked it some weeds but then only ran about half power the rest of the way to the dock, when I got to the dock and out of the water it would not restart, just turns over with no spark. I did a compression check, all were 120ish, and can even smell fuel so I'm certain its a spark problem. I went through the manuals spark trouble shooting. Stator and trigger resistance both checked out ok but after that I start getting some weird results from the ignition tests. to start I didn't have a 400VDC setting on my meter so used 600VDC and I could only get the rpms the starter turns it over, I'm sort of thinking that's part of the reason for the low readings??? anyway for the coil primary I get 0 (zero) volts, switch box stop circuit one is 15-20 volts on one and 0-10 volts on the other, stator low speed I get 20-25 volts and the high speed is 0-1 volt. All of these are way lower than what the chart says it should be at 400RPM, not sure of that's because the stator is bad or the RPMs are lower than 400.

    Based on what I'm reading it seems like it could be the switch boxes but could they have really gone bad at the same time? What else should I check or try before spending a ton of money on replacing both of them? The stator was replaced less then 20 hours ago (fall 2018), could it really have gone bad again? Could it just have come out of timing? I haven't pulled the flywheel off yet, not sure what I should look for if I do... Will likely pull it this afternoon and see if there's anything obvious since I'm sort of out of ideas now.

    Thanks,
    Doug


  2. #2

    Default Re: Electrical issue has me scratching my head

    try disconnecting the stop circuit and use a spark tester to check for spark.

  3. #3

    Default Re: Electrical issue has me scratching my head

    I thought I had tried that, but has been a few weeks since I last looked at it so just went out to try. I pulled one, then the other, then both. None of which had any type of change impact just turning over but not as much as a sputter.

  4. #4
    Join Date
    Nov 2011
    Location
    tennessee
    Posts
    4,661

    Default Re: Electrical issue has me scratching my head

    Does it have the TKS system?
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  5. #5

    Default Re: Electrical issue has me scratching my head

    Yes it does TKS. Is it possible the ECM could be bad?

  6. #6
    Join Date
    Nov 2011
    Location
    tennessee
    Posts
    4,661

    Default Re: Electrical issue has me scratching my head

    Yep......
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  7. #7

    Default Re: Electrical issue has me scratching my head

    I don't suppose there's any way to test to know for sure before forking over the 600.00 cost is there?

  8. #8

    Default Re: Electrical issue has me scratching my head

    Still wondering if there's any way to test it, trying to figure out a way to verify before buying new since its can't be returned if it doesn't fix the issue. From the time I bought it it always started kind of hard, I thought it was due to float bowls being empty. I would turn key on/off a few times to cycle fuel pump and then press the little bubble to drain fuel from top carb to lower carbs then would still crank for a bit. Now I'm sort of wondering if that is the ECM as well with the electric choke, maybe its been buggy for some time?

  9. #9

    Default Re: Electrical issue has me scratching my head

    Anyone have any idea if there's any major difference in ECMs on the older to newer 175 sport jets? I found one I can use, if nothing else to test but it is from a later model engine, the mercury part numbers are 85399503T (superseding 853955 3 that's in there now) and the one I have to try is "853995 4". looking between the part numbers on both engines they have the same coils, the same stator, and same wire harness. difference is in the ECM, Volt regulator, and switch boxes. I'll look both over real well before deciding but I might just swap all three over to my engine.

  10. #10

    Default Re: Electrical issue has me scratching my head

    Did you use a spark tester to know for sure you're not getting spark?

  11. #11

    Default Re: Electrical issue has me scratching my head

    How many volts were u getting from stator ?

  12. #12

    Default Re: Electrical issue has me scratching my head

    I did, yes for sure no spark. I got 20-25 volts on both the low speeds 0-1 volt on both the high speeds. Those readings are at "cranking" RPM since its not starting. They are still honestly still lower then I sort of expect but it does pass résistance testing and was replaced with just a light season on it.

  13. #13

    Default Re: Electrical issue has me scratching my head

    Did u disconnect rectifier/ regulator. And stop switch wire. ?

  14. #14

    Default Re: Electrical issue has me scratching my head

    I think so... I disconnected the black/yellow wires coming from the switch boxes (one, then the other, then both) no change. Did not do anything with regulator, which ones should I try disconnecting from there?

  15. #15

    Default Re: Electrical issue has me scratching my head

    Well got donor boat home, changed out ECM and regulator and still nothing so I'm back to the switch boxes... will wait until later tonight or tomorrow morning to mess with those. If I get all three swapped out and it's still not running I'm not sure what I'm going to do next....

  16. #16

    Default Re: Electrical issue has me scratching my head

    We got fire!! Wired up the new switch boxes and it fired right up. good stuff. Thanks all for the help, this will get me back out on the water for the season!!

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