1998 Mercury 225 (Carb) Alarm or ignition issue

Alan Hardesty

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Jul 22, 2014
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Running along and the engine suddenly (for 1/2 second) losses all power, alarm on engine control panel chirps once (similar to sound when starting engine), after the 1/2 second the engine power is restored. Another interesting thing, the GPS shuts down when this happens but other less sensitive electronics stay energized (the GPS is not wired to ignition key). It acts almost like the ignition key is turned off and back on as fast as you can.
T/S so far: Batteries both check perfect using a load tester, analog dash volt meter reads just under 14 VDC, No water in the fuel tank, engine oil tank is full, engine water temp is 135-140. In a 30 minute period of running in the bay it happened 3-4 times randomly but seemed to happen at higher RPM's. I didn't see this happen at RPM's below 2000 or so. There is plenty of power all the way to WOT. I plan to check the ignition wire connectors in the console and engine. When I winterized the engine last year I checked everything and all the connections in the engine had dielectric grease on all the connectors, so I don’t expect to find anything easy.
 

bilge rat jim

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Jun 28, 2012
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Sounds like a momentary loss of power to the ignition circuit (technical name- GREMLIN). I would start by inspecting every connection in both the ignition and stop circuits. You may able to eliminate the stop circuit from the picture by disconnecting it and a water test. Also look at the wiring- look for wires with eroded insulation, flat spots, abnormal bends, etc.
 

Alan Hardesty

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Jul 22, 2014
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Thanks for the advice. I will check all connections in motor and include the kill and ignition switch and all wiring between..
Stop circuit includes Kill switch and ignition switch?... Is there anything else? The 1998 drawing didn't show a module or other sensors. When the kill switch is in the run position Is the switch normally open or normally closed?
 

bilge rat jim

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Jun 28, 2012
Messages
330
The kill switch is open circuit when running, closed (to ground) when stopped.
 

enginepower

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Jul 5, 2014
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you have a loose connection somewhere i'm sure....most common is the battery cables....clean them up and see what happens
 

That's Right

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Jul 22, 2014
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I am having the same problem with my 1997 Mercury 225 offshore, can you let me know what you find out to be the problem. I don't know if I want to turn the boat in a marina to have it fixed or try to fix it myself. There was a post I found on here that described the same thing going on with his motor, but the solution was never posted on what was wrong with his motor. So if you don't mind, can you call me and we can talk, my number is 703-threezeronine 0412. thanks!
 

That's Right

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Jul 22, 2014
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Alan sorry I did not read all the instructions on posting on your thread. If you get a chance please call me to discuss the same problem ghat I am having. Stan 703-309-0412. Thanks.
 
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