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TOPIC: Need some advise on running a compression test
Need some advise on running a compression test 14 years 10 months ago #455
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I need to run a compression check on an engine with electronic ignition. It's a Johnson, with individual coils for each of the four cyls. If I unhook the orange wires from each coil going to the ignition pack, will that work to not damage (burn up) anything in the ignition system? Any advise would be greatly appreciated.
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Mark
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Re:Need some advise on running a compression test 14 years 10 months ago #458
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If you do that the HV Capacitor in the power pack is still gonna be charged with nowhere for the juice to go. My thought would be to make sure the plug leads were all grounded to the block. BUT, I'd consult the shop manual 1st, or a qualified tech.
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Re:Need some advise on running a compression test 14 years 10 months ago #460
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Thanks Bruce, think I better do just that before I screw something up.
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Mark
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Re:Need some advise on running a compression test 14 years 10 months ago #464
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Mark, Disconect the battery and run jumper cables to the + connection on the starter and the - connection to the powerhead.
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Re:Need some advise on running a compression test 14 years 10 months ago #469
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Thanks, that makes sense. Just send power to the starter, not the ignition.
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Mark
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Re:Need some advise on running a compression test 14 years 10 months ago #472
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Mark, That's the idea. Plus you can just screw in the compression gauge and touch the cable to the starter (it will spark some, no harm done) and release after a few revolutions while you are at the motor watching the gauge.
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Re:Need some advise on running a compression test 14 years 10 months ago #495
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Hello just put a spark plug on each lead and ground electrodes to block acn be done if you have a few alligator clips and wire.
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Re:Need some advise on running a compression test 14 years 10 months ago #497
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Re:Need some advise on running a compression test 14 years 10 months ago #502
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Many thanks, I really appreciate the help. One of the few good things about getting older is learning to get advise from someone who knows, instead of plunging in THINKING I know how to do it.
To quote Robert L, "I love this place"! |
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Mark
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Re:Need some advise on running a compression test 14 years 10 months ago #568
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Great news, the compression test came out good, all four holes read just shy of 150lbs! And thanks to the tutorial, I also ran a spark test and everything is snappin'! I devised my own spark plug grounding system, crude but effective.
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Mark
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Re:Need some advise on running a compression test 14 years 10 months ago #632
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Yup, like he said, that's how I do my tests, ignition off and jump the starter.
No risk of high voltage or ignition damage. Randy |
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