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  1. #1
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    Default Electronic ignition conversion

    Hi guys,

    I have a 1982 boat powered by a Mercruiser 120 GM 2.5L engine. I've had some grief in the past with the points and I want to convert it to an electronic ignition.

    I found the following link but I don't feel 100% confident that this is the correct part for my motor.
    Pertronix Ignitor Ignition Coil Wires Mercruiser 120

    Would someone be able to help me confirm?

    Thanks!
    Rob

  2. #2
    Moderator Bondo's Avatar
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    Default Re: Electronic ignition conversion

    Ayuh,.... If yer serial numbers fall within the ranges, Ya, it oughta work,...

    gnitor system and flamethrower coil 12V Negative Ground for
    110 from serial 1537370 to 2044033
    120 from serial 1666601
    140 from serial 2508261
    165,170,180,190 from serial 6916779
    470 from serial 4208730
    470R from serial 6218037
    485 from serial 5685394
    488R from serial 617029
    Any Grease is Better,..... Than No Grease at All.......

  3. #3
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    Default Re: Electronic ignition conversion

    Thanks Bond-o!

    Quote Originally Posted by From Mercury site
    You can locate the MerCruiser serial number label on either the the side of the engine or on top of the flame arrester cover.
    Is this serial number on an identification plate or stamped into the block casting?
    I don't have my boat nearby. I could call to get the number read back to me but it would help if I can let them know where to look.
    Last edited by Nijkampr; July 24th, 2013 at 10:49 AM.

  4. #4
    Captain
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    Default Re: Electronic ignition conversion

    I would not go with the Ignitor, I would advise going with the Ignitor II (91146A) paired with a Flamethrower II coil (45011, oil filled or 45111 epoxy). The Ignitor II is newer technology, with some added features, and with the Flamethrower II will give a hotter spark. A little more expensive but in the long run worth it IMHO. Here is the info on both: http://www.pertronix.com/catalogs/pd...ition_conv.pdf and the coils http://www.pertronix.com/catalogs/pd...2012_coils.pdf
    Last edited by stonyloam; July 24th, 2013 at 11:30 AM.
    Terry
    87, 4WINNS H 190
    470/Alpha I

  5. #5
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    Default Re: Electronic ignition conversion

    I don't think the 120 is going to see any performance increase with the Ignitor II. I understood the Ignitor II was better for custom tunes or modified engines. I plan to leave mine stock. My understanding was that the dwell was adjustable on the version 2 but looking at the material suggests that the dwell is adjusted dynamically by the controller? How does it do that?

  6. #6
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    Default Re: Electronic ignition conversion

    As I understand it, in the past the Ignitor could be damaged by leaving the key on, don't know if that is still true. How it works? Just a guess here but it looks like there is a tachometer in the module and a linked timing circuit that increases dwell (length of time current flows through the coil, eg. points are closed in a points ignition) to maximize the spark at a given RPM. All done by a microprocessor. One thing, before you put in the electronic module put in a new set of points, and adjust the dwell. When you remove the old distributor plate seal it in a bag and keep it some place handy just in case the electronic module should fail sometime down the road. I keep mine in the glove box LOL.
    Terry
    87, 4WINNS H 190
    470/Alpha I

  7. #7
    Commander thumpar's Avatar
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    Default Re: Electronic ignition conversion

    Yep, get the ignitor II along with the flamethrower II. I have that on my 120. Like stonyloam posted the ignition module will burn out if you leave the key on with the original Ignitor.
    83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

    1996 Crownline 202BR
    5.7l EFI 0f791070
    Bravo I drive

  8. #8
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    Default Re: Electronic ignition conversion

    Do you have part numbers? I'm having trouble confirming if I need Pertronix 91146A
    Last edited by Nijkampr; July 24th, 2013 at 04:45 PM.

  9. #9
    Commander thumpar's Avatar
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    Default Re: Electronic ignition conversion

    Quote Originally Posted by Nijkampr View Post
    Do you have part numbers? I'm having trouble confirming if I need Pertronix 91146A
    That is the one I used on my 1983 120.
    83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

    1996 Crownline 202BR
    5.7l EFI 0f791070
    Bravo I drive

  10. #10
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    Default Re: Electronic ignition conversion

    Quote Originally Posted by thumpar View Post
    That is the one I used on my 1983 120.
    Thanks!

  11. #11
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    Default Re: Electronic ignition conversion

    Yes, the Ignitor can be damaged if the key is left in the "on" position. The Ignitor II incorporates auto-shut off features that keep it from being damaged if the key is left "on".
    1976 Mark Twain 200VBR w/Mercruiser 233 (Ford 351w) "Heart & Soul"

  12. #12
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    Default Re: Electronic ignition conversion

    Does anyone know what the output of the standard coil is? I just replaced the coil and if I can use it, it would save me $50. Thanks.

  13. #13
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    Default Re: Electronic ignition conversion

    Should be no problem, just if it is a stock coil you need to keep the purple resistance wire on the coil, and run a full 12volts to the Ignitor or (II). Best place to splice in is at the choke connector. I used solder and coated with liquid tape. Stock coil should be around 30,000 V.
    Last edited by stonyloam; July 24th, 2013 at 06:54 PM.
    Terry
    87, 4WINNS H 190
    470/Alpha I

  14. #14
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    Default Re: Electronic ignition conversion

    Quote Originally Posted by stonyloam View Post
    Should be no problem, just if it is a stock coil you need to keep the purple resistance wire on the coil, and run a full 12volts to the Ignitor or (II). Best place to splice in is at the choke connector. I used solder and coated with liquid tape. Stock coil should be around 30,000 V.
    Where would I find the choke connector?

  15. #15
    Commander thumpar's Avatar
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    Default Re: Electronic ignition conversion

    You may not have an electric choke so you would need to find another 12v source. When I did mine I ran it along side the resistance wire to keep it clean then rewrapped the wire bundle.
    83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

    1996 Crownline 202BR
    5.7l EFI 0f791070
    Bravo I drive

  16. #16
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    Default Re: Electronic ignition conversion

    Is the resistor inline in the wire to the coil? If so, I can trace that wire and tee in before the resistor. Then leave the wire intact in the event I need to revert in an emergency.

  17. #17
    Commander thumpar's Avatar
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    Default Re: Electronic ignition conversion

    The wire is the resistor.
    83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

    1996 Crownline 202BR
    5.7l EFI 0f791070
    Bravo I drive

  18. #18
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    Default Re: Electronic ignition conversion

    Look for the purple wire on the coil +. That is your resistor wire and it should go back to a connector on the electric choke (if you have one). You would pick up the 12V by splicing in near the connector.
    Terry
    87, 4WINNS H 190
    470/Alpha I

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