SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: hotblooded454 on July 16, 2013, 12:38:24 PM
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We have a 1990 mantra gullwing jet boat with a 454 bbc. When we turn off the ignition the engine continues to run and the electronics (gauges) don't turn off. We tried replacing the ignition, and the wiring seems to be good. It is not the alternator because we disconnected it and it still happens. Any ideas?
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Does it have an hei? If it does are those leeds hooked up correctly
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You're wired incorrectly somewhere - your switch does nothing but start the engine, right? Somehow your power is bypassing your switch, look under the dash and follow your wires from the switch perhaps you can find where the power is coming from. If that doesn't work pull fuses one at a time until the engine dies, then follow that circuit.
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my guess is in the 3 bundles of wires hooked to the switch, on the cold side you have a hot wire. Pull the wires off the RUN side of the switch, separate them then check for current with a multi-meter, or circuit tester. If one is HOT it's on the wrong side of the switch.
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You're wired incorrectly somewhere - your switch does nothing but start the engine, right? Somehow your power is bypassing your switch, look under the dash and follow your wires from the switch perhaps you can find where the power is coming from. If that doesn't work pull fuses one at a time until the engine dies, then follow that circuit.
what he said
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Thanks! It does have an hei. Will do what you guys suggested. Will let you guys know if it works/doesn't work. Thanks again!
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NOT AN IGNITION PROBLEM!!
The alternator excitor wire is feeding back juice to the coil wire through the “ign.” terminal on the switch. You need to install a diode on the excitor wire. The Radio Shack part number 276-1661 this is a 6A 50V rectifier diode ($2.49/pk of 4). Wire it up with the stripe toward the alternator.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.67-72chevytrucks.com%2Fvboard%2Fattachment.php%3Fattachmentid%3D318391%26amp%3Bstc%3D1%26amp%3Bd%3D1196463678&hash=68e376e1703f44b682e93f600cf47e3d5980df1f)
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Looking at the photo of your switch, I believe you have it hooked up wrong... are the 2 red wires on the right side HOT? (POSITIVE)
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[attachimg=1]
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I disagree about the diode - he says all his gauges and everything still work. If it was the diode the engine would run but everything else would turn off.
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And I unhooked the wires from the alternator and the problem persisted. As for the ignition I will double check and test the wires. Here is a better pic of it.
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The red on the ignition is a purple wire just the sleeve on the connector is red
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As for the two red wires. They are booth hot.
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much better view, thanks... on the ING lug, is there only one wire there or do I see a 2nd one hideing behind the tape?
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Yes there are 3 purple wires total 2 into the one connector and another separate one with its own connector hiding behind the tape.
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Have you checked to make sure one isn't hot? That is the most likely place for your wireing to get crossed.
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Ok. We are going to start going through the wiring now. Thank you for your help. We will try everything you suggested. And I will post on here if we figure it out or not. Thanks again!
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Check the hot leed on the hei. If you have it to 12v power all the time, it never loses power and the motor will j
Keep running until it runs out of gas.
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One of the purple ignition wires is hot. The one that comes from the harness.
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BINGO!
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What should we do with it?
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Problem fixed! Battery cable was contacting the starter. Thank you for your help!