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  1. #1

    Angry Volvo Penta AQ125A Ignition Problems

    I have a '82 Bayliner with a Volvo Penta AQ125A engine. There has been a recurring issue with burning out coils. It seems that you can go out on the lake 2-3 times before it fries. We get towed to shore, replace the coil, and within minutes are bounding accross wavetops once again. Just before the coil dies the engine starts skipping and sputtering and the tach jumps all over. If you open up the throttle it will rev and then bog and rev and then bog...rinse, lather, repeat. This goes on for a while until you are about 400 feet from shore and then the engine dies and will not start again. We get towed to shore, replace the coil, and within minutes are bounding accross wavetops once again. When we go to replace the coil it is almost too hot to touch. Needless to say this has been a frustrating experience. I have tried to convince my father to name the boat "Tow ME!", but he just shoots me a dissaproving look that only a father can.
    We have tried factory coils, aftermarket coils, coils with internal resisters, coils that need external resisters, red ones, blue ones...all burned out after a few hours of use.
    What could cause this issue? Bad condenser? Incorrect points gap? Bad coil ground? Gremlins? As much as I enjoy crawling into a hot engine compartment while bobbing around at the mercy of the waves as the landing fades into the distance, I would like to find a solution to this issue. It's getting expensive to bring a spare coil with me every time I use the boat. Thanks in advance for your help.

  2. #2
    Captain
    Join Date
    Jun 2008
    Location
    Chisago Lakes, MN
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    3,408

    Default Re: Volvo Penta AQ125A Ignition Problems

    It could be the tach. One of the wires on the coil goes to the tach. Should be the grey one. disconnect it and run it and see.

    Maybe a professional will chime in. Or someone whose had that problem before.

    I haven't seen this issue come up lately.

    Please post the fix if you find it.

    Please put the factory spec parts on the boat before continuing. You need either an internal resister coil or an external ballast resistor. Are your points burning up as well?
    Last edited by captmello; July 25th, 2009 at 10:54 AM. Reason: Add info
    '88 Baretta Success 200
    Volvo Penta AQ260/275

    '96 Weeres Suntanner 24
    '01 90hp Johnson

  3. #3
    Seaman Apprentice Peter1950's Avatar
    Join Date
    Jun 2009
    Location
    Liberty Lake, Wa
    Posts
    48

    Default Re: Volvo Penta AQ125A Ignition Problems

    I have doubts in the tach. The signal for the tach is coming from the points. Though the connection is at the coil, it doesn't use the coil for any purpose for the tach. Could be the external resistor, but I don't entirely understand its purpose.
    Peter - 1983 Bayliner Capri 19ft Bow Rider - Volvo Penta engine and 275 stern drive. See my videos at: http://www.youtube.com/watch?v=qfAmFa-De4k

  4. #4
    Petty Officer 1st Class
    Join Date
    Mar 2009
    Posts
    351

    Default Re: Volvo Penta AQ125A Ignition Problems

    the connection for the tach is still hooked to the coil, so yes, if tach is shorting, it could fry the coil. the resistor steps the voltage down for ignition, and must be there if your system is supposed to have it. and i believe it is. then it's a matter of which resistor, cause you must have the right one. yes, take tach wire off, but also check every single wire, check plugs, plug wires, recheck gap AND dwell, timing.
    MY ADVICE... UH, YEAH, WHAT HE SAID.

  5. #5

    Default Re: Volvo Penta AQ125A Ignition Problems

    Quote Originally Posted by maxxman04 View Post
    the connection for the tach is still hooked to the coil, so yes, if tach is shorting, it could fry the coil. the resistor steps the voltage down for ignition, and must be there if your system is supposed to have it. and i believe it is. then it's a matter of which resistor, cause you must have the right one. yes, take tach wire off, but also check every single wire, check plugs, plug wires, recheck gap AND dwell, timing.
    MY ADVICE... UH, YEAH, WHAT HE SAID, All of This would be a good test to try, Also make sure all your power and ground wire/cables are clean and tight to the batteries and engine. And make sure the dwell, timing are right on at 100% to specks.Good luck with it.http://www.volvopentastore.com/Maint...view_id.362365. http://www.volvopentastore.com/Elect...view_id.333007. http://www.volvopentastore.com/AQ125...view_id.342835. Here is some links to look up the right parts for your engine in case you need them.

  6. #6

    Default Re: Volvo Penta AQ125A Ignition Problems

    I have a different problem that may be coil-related. I have replaced most of the ignition parts (and fuel pump) and everything is in spec. Both the carburetor and distributor have been serviced. Fresh gasoline, new fuel line. The engine will start easily, idle nicely, and go to 4000+ rpm without load. Ignition timing is 6 deg at idle (900 rpm) and 32 deg at 4000 rpm, so the distributor is advancing OK. Under load it bogs down above 1500 rpm and dies. The question in my mind is this: The OEM coil calls for an external resistor. I replaced it with an automotive coil (intended for the appropriate Volvo car) from O'Reilly, but I don't know if it calls for an external resistor. Has anyone used a coil like this successfully? The coil does not get hot and fry.

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