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jamoore
08-30-2001, 08:36 AM
Thought I had it fixed. 1987 175hp Mariner on 20'center console fishing boat. Initially lost fire on one side of engine. Tested switchboxes(tested ok) and then replaced stator. Ran great, started better than ever before (years) but had cooling problems. Changed impellor,replaced stats w-restrictors, replaced poppit, all these fixed cooling problems. Even managed to get temps close between banks by using different size discs. Took it out last Sunday and ran perfect for 2 hours. Never missed a beat, temp good. Took it out last night and wouldn't run for s--t. Checked and found no fire again on left bank except this time top cylinder showed week constant current( using a spark tester between coil and plug that has light, light steady glows but weak on this plug) Didn't have time to check further due to darkness. Hope it isn't stator again, they aren't cheap and if it is gone again then obviously something is causing it to go bad. Was hoping I could get some more thoughts from you guys on this. I have to say I am learning a lot about this engine lately and actually have enjoyed working on it. I can't thank the folks here enough for the advice and guidance you have given in the past. If I can get this one squared away then maybe I can get my Mirage in the water this year. Been re-doing that one for 2 years (on and off) and haven't gotten to ride yet. Thanks again! Joey

us1
08-30-2001, 09:11 AM
Sounds like a switch box, the only good thing about that is you still have a good working one to test with. Reverse the switch boxes and see if the problem moves to the other side of the motor. This will tell you if it’s the stator or the switch box. Make sure the switch boxes are grounded to the switch box mounting plate and the mounting plate is grounded to the block. Nothing burns up this stuff faster than bad grounds.

Talon2.5
08-30-2001, 09:27 AM
probably wont help ya but is info for everyone in the future with trouble shooting some plug problems.........

intermittent, weak or no spark put at TWO spark plugs (ONE plug from each bank of three cylinders) usually is caused by a bad trigger.


Intermittent, weak or no spark output at three spark plugs (a complete bank of three cylinders) usually is caused by a bad stator or switchbox.



Intermittent, weak or no spark output at any one spark plug (single cylinder) usually is a bad coil or switch box


straight from the book verbatum, if any one needs it in the future .............later skip