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1996 7.4 Has Low Spark From Coil

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Old 04-23-2009, 04:33 PM
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Default 1996 7.4 Has Low Spark From Coil

what is a good way to test for this prob or ? any ideas would help thankyiou james
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Old 04-23-2009, 05:13 PM
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touch your tongue to the coil wire while holding a 100 watt bulb, have a friend bumb the key...
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Old 04-23-2009, 05:27 PM
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Default engine id # of 773374 can anyone tell me what ign system it has pz

could any tell me what ign system this mercruiser 7.4 has engine id # is of 773374
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Old 04-23-2009, 07:42 PM
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Not a good serial number you should have a zero and a letter before the numbers. Probably has Thunderbolt 4 or 5. Weak spark would probably be the coil, the module in the dist will either work or not and the amplifier usually doesn't cause weak spark. Are wires and plugs replaced?
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Old 04-23-2009, 11:42 PM
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Default yes number is 0f 773374

that is on the tag on the motor
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Old 04-24-2009, 12:58 AM
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Weak spark from coil is most likely a bad coil. Switch it out for $40.
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Old 04-24-2009, 07:19 AM
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Didn't see the 0F, this engine has the Delco ignition, not Thunderbolt. These coils also go bad and there is a module inside the ignition that goes bad also. This is an automotive ignition and parts are available anywhere.
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Old 04-24-2009, 10:47 AM
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Merc part # for the coil is #898253T27 and they are $115.20 each and the module which I'm betting is the problem is #811637001 and cost is $133.25 and don't use automotive parts on a boat that's just asking for trouble.
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Old 04-24-2009, 01:08 PM
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You can easily use an automotive coil as long as you get one for off/road high vibration.
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