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Mercruiser loosing power to the ignition switche

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Old 08-30-2018 | 08:42 AM
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Smile Mercruiser loosing power to the ignition switche

Hi All;

I have traced an intermittent issue where my port engine losses power to the ignition switch. The power is running thru a breaker and and I have verified the issue is not in the breaker. My question is does this power lead run thru another relay or ECM or is it straight from the battery. My next check will be to put a trace on it using a cable tracker.

Thanks in advance.
Vince
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Old 08-30-2018 | 09:26 AM
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Should go through the kill switch............
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Old 08-30-2018 | 09:28 AM
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Thanks.. I'll check this next..
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Old 08-30-2018 | 11:35 AM
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Since I recall a few of your posts as you have 496 s Merc but how in the world can anyone help with anything of this when no one else even knows your app nor an engine serial number per how its all set up. And is your app stock ? I am amazed at this. One can look at this what marine engine - what set up and model and year what components and so forth.

Ok since I believe and or recall you do have Merc 496 s --- so do you have DTS or not - is your ign set up with smartcraft and that gauge package ? Way too many unknowns here to even offer help. How many batteries and those installs for your app ?. All your systems corrosion free including all wiring -- terminals - connections and so forth ?

Sorry to sound out of line here and correct me if I am wrong but what in the world do you have for applications and set ups ?

Last edited by BUP; 08-30-2018 at 11:38 AM.
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Old 08-30-2018 | 11:48 AM
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I had a similar intermittent issue that I chased for years on my 502mpi. My purple wire coming from the alternator was rubbing on an engine mount plate and causing a short.
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Old 08-30-2018 | 12:13 PM
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Thanks all.. The two wires coming into the switches are low gauge (10 or 12) and are running though separate breakers. The wires coming from the emergency kill switch are 16 gauge so they are not directly connecting to the ignition switches. I did just lose the starboard Alternator and am awaiting a replacement. That is the side that is misbehaving.

Stupid me but perhaps I'll hold off until after the new alternator is installed.

The boat is a 2006 Chaparral Signature 350
twin 496 MAGs / SN 0W354325 ( Representative)
No DTS but I do have SMARTCraft (I installed it)

Thanks
Vince
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Old 08-31-2018 | 06:28 AM
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also ck main harness plug at engine, pull apart clean reconnect
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Old 09-11-2018 | 05:40 AM
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Problem Solved; Had to purchase a PCM 555 Service Manual #33, and found that the engine power is routed typically from a battery / switch to the starter. The engines pull their primary power from the starter connection via a 90A fuse.
I had a starter going out (grinding and intermittent) and the power lead had loosened to the point that the electrical connection was bad. So when I changed out the starter and cleaned the connections every thing else cleaned up.
So that Alternator on Starboard side was replaced and is now working and the starter on Port is now new. All is as it should be.
The full PCM Service Manual is much more complete than the online versions. Glad I have it now.

Take Care
Vince
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