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  1. #11
    Join Date
    Jun 2020
    Posts
    8

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    I have a Mallory distributor. Update took it out after the new coil ran good at my house as soon as i hit the water ran like shit fuel pressure was down . Had to pump the gas just to get it rolling. So i replaced the pump and a little better pressure but still same thing now it just runs rough at idle! Any suggestions?

  2. #12
    Join Date
    Jul 2010
    Location
    N.W. Suburbs Chicago, IL
    Posts
    2,307

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    Can you have a friend come with you and get some video to post on YouTube and link here? I would also include video of it running on the hose at home, basically document the whole thing of what you are experiencing and post the links here for us to check out.
    '86 Comp TS6M - Reborn 2016
    Riding a HO Sports CX Ski

  3. #13
    Join Date
    Jun 2020
    Posts
    8

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    yeah i probably can .
    so update . i replaced the solenoid that controls the starter and had a ignition stud that powers the coil because i volt at the coil are around 6v and it goes up with the rev it. when i had it idling i removed each wire and found 1 3 and 7 didnt change the idle as if there were not firing. im assuming maybe the distributor need to be replaced?

  4. #14
    Join Date
    Jul 2007
    Location
    Flowery Branch Georgia
    Posts
    2,742

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    That i term is usually not used with electronic ignition . I am not familiar with the mallory set up . All of my boats are running DUI . If you have 3 dead cylinders you should start with a compression test .

  5. #15

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    I would put the D.U.I distributor in and call it a day. I fought my electronic Mallory ignition for a little while. The coils kept overheating and having problems. The boat would miss when the coil heated up and if you were idling waiting for a skier the boat would die. It wouldn't start until I soaked a rag in water and through it on the coil or sat and let it cool down.
    Threw the D.U.I distributor in and fires up on the first key turn and can run and idle all day long.
    Spend the money and enjoy the boat.

  6. #16
    Join Date
    Jun 2010
    Location
    Ontario, Canada
    Posts
    171

    Default

    Quote Originally Posted by covertcombatant View Post
    I would put the D.U.I distributor in and call it a day. I fought my electronic Mallory ignition for a little while. The coils kept overheating and having problems. The boat would miss when the coil heated up and if you were idling waiting for a skier the boat would die. It wouldn't start until I soaked a rag in water and through it on the coil or sat and let it cool down.
    Threw the D.U.I distributor in and fires up on the first key turn and can run and idle all day long.
    Spend the money and enjoy the boat.
    100% Agree. I had a similar problem with my 85 Comp for years and could never figure it out. Turns out it was a bad coil, ballast resistor, and bad wiring.

    Another thing to check is to see what voltage you are getting at the positive side of the coil. They typically like to see 9-9.5V; if you are seeing over 10V, I would look at how it is wired (this also happened on my boat...full 12V was being sent to the coil which caused overheating and after time terrible spark".
    1985 Supra Comp TS6M
    351 Windsor - 240 HP
    Velvet Drive - 1:1
    Fully Rebuilt

  7. #17
    Join Date
    Jul 2020
    Posts
    2

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    Anyone know the wiring for the ballast resistor? I have a feeling mine is wrong from previous owner

  8. #18
    Join Date
    Jun 2010
    Location
    Ontario, Canada
    Posts
    171

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    Essentially you want is to make sure you have 12V going to one side of the ballast resistor, then on the other side of the resistor you should have around 9V so you can take a wire from that point on the resistor and feed the positive side of the Ign Coil. Those coils only want 9-10V; if they are getting full power during operation they could be seeing 13 to 14 V because the system is charging which causes the coil to overheat and give a weak spark.

    Another key part is that you want to have an "externally resisted coil" and a points based distributor. You can search YouTube on how to test what coil you have.



    Also watch this video series from lively (a member here) made a while ago. This really helps explain it in detail.

    https://www.youtube.com/watch?v=7LyJtyJPSEM When he had it wired wrong.

    https://www.youtube.com/watch?v=9-N2OgZGpzo When he changed the wiring so the positive coil was only receiving power through the resistor.
    1985 Supra Comp TS6M
    351 Windsor - 240 HP
    Velvet Drive - 1:1
    Fully Rebuilt

  9. #19
    Join Date
    Jul 2020
    Location
    Huntsville, AL
    Posts
    5

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    So I had this problem on my 1989 Supra Sunsport...has electronic distributor changed ignition coil, fuel pump, spark plug wires, checked timing and still ran with a miss or a backfire...changed plugs to a hotter heat range and still a miss...then checked bolts on the Holley Carb...they were loose...tightened the carb bolts and it has run great ever since? I think it was both improper plugs AND air getting into carb from loose bolts!

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