Mercury 6.2 ECT DTS Axius Voltage Issue

[tpenfield]

No expert by any means but remember my issue?
I turned switches OFF and smartcraft would not power off until I disconnected clean power. I'm sure there is more then just that, but it would not power down prior

Yes, maybe that is a keep-alive and directly connected to the battery. I think my set-up is like that. I just got to compare things to how the port engine is set up.

 

[dubs283]

Yes, maybe that is a keep-alive and directly connected to the battery. I think my set-up is like that.

Clean power has been mentioned/explained multiple times by multiple different members in this very thread

 

[bruceb58]

When I go up to my boat in a few days, I will put my Diacom on with the battery switch on and off and see what I get.

 

[tpenfield]

OK - today is going to be 'clean power' day. I think I found the connector on the engine, just need to tap into it for voltage readings.

 

[tpenfield]

The outdrives are now installed. Every years as I'm installing them I say to myself . . ."gotta get a boat with outboards . . ."

Working on the clean power . . . Port engine voltages are normal and what you would expect.

The 11.8v that I'm seeing on the starboard engine with the battery off appears to be coming from the port engine. If I disconnect the port engine battery, the 11.8 volts on the starboard goes to 0.

IIRC, on a twin engine installation there is some sort of interconnect between the two? I can't quite remember, but I believe one of the engines is supposed to be the 'master' and the the other is supposed to be the 'slave' from a controller perspective.

I think I fried my DVM, so got to get another one to test out some amps

 

[tpenfield]

Quick Update . . .

I replaced the circuit breakers for Main power and Axius clean power. Not sure if they were a problem, but they are replaced.

>>> I think I have clean power (12.85 volts)
>>> Still getting 9.2 volts at the ignition wire. I swapped the ignition keys and the 9.2v stayed on the stbd engine.
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STARBOARD ENGINE

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Clean Power (Red/Blk) is 12.85 with ign. OFF and 12.0 with Ign. ON

If I turn off the stbd battery after having turned on & off the ignition, I still get the MPR buzzing.
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STARBOARD ENGINE VIDEO
View attachment Clean-Power-1.mov
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The voltage on the 'green' DVM is the Red/Pur (and Red/Pink) wires.
The voltage on the 'orange' DVM is Clean Power (Red/Blk)

If I turn the stbd battery back on the buzzing stops OR . . If I disconnect the port battery the stbd MPR stops buzzing.

Port engine is normal voltages across the board. Ign. wire (purple) is 11.4v with Ign. ON.

 

[tpenfield]

Here is the clean power on the port engine . . .

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The 2 CB's . . . Starboard side.

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The engine clean power is on a third lead from the STBD isolation post it does not appear to have a CB, which I think is as it should be; Thus 'clean'.

 

[tpenfield]

Wondering if I should unplug the Alternator Excite connector . . . as a test.

 

[muc]

The outdrives are now installed. Every years as I'm installing them I say to myself . . ."gotta get a boat with outboards . . ."

Working on the clean power . . . Port engine voltages are normal and what you would expect.

The 11.8v that I'm seeing on the starboard engine with the battery off appears to be coming from the port engine. If I disconnect the port engine battery, the 11.8 volts on the starboard goes to 0.

IIRC, on a twin engine installation there is some sort of interconnect between the two? I can't quite remember, but I believe one of the engines is supposed to be the 'master' and the the other is supposed to be the 'slave' from a controller perspective.

I think I fried my DVM, so got to get another one to test out some amps

Outboards ---- be careful what you wish for. A pair of 350hp I/Os with fresh water cooling is about $58,000 A pair of 350hp Verados are about $74,000
But the gift keeps on giving. Mercury Marine sells something called Product Protection -- think "extended warranty"
5 year plan for a pair of 350hp I/Os is $5,400
5 year plan for a pair of 350hp O/Bs is $16,900
So Mercury (who has a VERY good idea how much breakdowns will cost) thinks that for those 5 years of limited coverage it will cost a little more then 3 times more for outboards!
Another little fact, Merc is happy to sell you 2 more years (total 7 years) on an I/O for $1,000 each. They will not sell you anything over 5 years on O/Bs Kind of makes you wonder what they know about years 6 and 7 on O/Bs?
Don't get me wrong, outboards have a lot of advantages in some situations. But $$$$$ isn't one of them.

"The 11.8v that I'm seeing on the starboard engine with the battery off appears to be coming from the port engine. If I disconnect the port engine battery, the 11.8 volts on the starboard goes to 0."
This shouldn't happen, something is miss wired. I really think you need to follow these wiring harnesses.

Back before DTS there was a harness between the engines, called a master/slave harness. Shouldn't have one on your engines. Master/slave is done in the computers via G3. Like I said earlier, there shouldn't be any electrical connection between the engines.

And turning off a battery switch should never affect clean power.

 

[tpenfield]

The ALTERNATOR !!!

I disconnected the excite wires from the alternator and the Purple wire voltage with ignition ON is up to 11.5 v, same as the port engine. The clean power stayed a bit higher 12.4v vs. 12.0 with the alternator excite connected.

I still get the buzzing when I turn the stbd battery switch off, but progress.

 

[muc]

Most DVMs have a fuse inside for amps, might just need to replace it.

Clean power needs a fuse. It must be protected.

I would be very interested in where those two circuit breakers are getting power from and what they power.

The voltage raising .4 volts with the excite disconnected is a bit much, maybe time to do some voltage drop tests while the system is under normal load.

 

[tpenfield]

Outboards ---- be careful what you wish for. A pair of 350hp I/Os with fresh water cooling is about $58,000 A pair of 350hp Verados are about $74,000
But the gift keeps on giving. Mercury Marine sells something called Product Protection -- think "extended warranty"
5 year plan for a pair of 350hp I/Os is $5,400
5 year plan for a pair of 350hp O/Bs is $16,900
So Mercury (who has a VERY good idea how much breakdowns will cost) thinks that for those 5 years of limited coverage it will cost a little more then 3 times more for outboards!
Another little fact, Merc is happy to sell you 2 more years (total 7 years) on an I/O for $1,000 each. They will not sell you anything over 5 years on O/Bs Kind of makes you wonder what they know about years 6 and 7 on O/Bs?
Don't get me wrong, outboards have a lot of advantages in some situations. But $$$$$ isn't one of them.

"The 11.8v that I'm seeing on the starboard engine with the battery off appears to be coming from the port engine. If I disconnect the port engine battery, the 11.8 volts on the starboard goes to 0."
This shouldn't happen, something is miss wired. I really think you need to follow these wiring harnesses.

Back before DTS there was a harness between the engines, called a master/slave harness. Shouldn't have one on your engines. Master/slave is done in the computers via G3. Like I said earlier, there shouldn't be any electrical connection between the engines.

And turning off a battery switch should never affect clean power.

Thank you . . . I'll see what I can find about the wiring for the clean power. I'm not so sure the manufacturer did the best job connecting the engine wiring, so it would not surprise me if they are in fact connected.

 

[tpenfield]

I might want to check the 2 alternator/3 battery isolator. That could be part of the problem . . . never like the looks of that thing.

 

[muc]

Thank you . . . I'll see what I can find about the wiring for the clean power. I'm not so sure the manufacturer did the best job connecting the engine wiring, so it would not surprise me if they are in fact connected.

Yes, I haven't worked for a Cruiser's Inc. dealer since the 80s so I can't comment on their build quality. They were a pretty good mid level boat back then.
But I do know ALL manufacturer's make mistakes (thank goodness, it supported my family for over 30 years!) after all they are built by humans and we all make mistakes.

Testing the isolator is easy, Just set the meter to ohms and test between the studs after disconnecting ALL the wires.

 

[tpenfield]

Yes, I haven't worked for a Cruiser's Inc. dealer since the 80s so I can't comment on their build quality. They were a pretty good mid level boat back then.
But I do know ALL manufacturer's make mistakes (thank goodness, it supported my family for over 30 years!) after all they are built by humans and we all make mistakes.

Testing the isolator is easy, Just set the meter to ohms and test between the studs after disconnecting ALL the wires.

The build quality of the boat is great, but the electrical system seems to be overly complicated. The accessory wiring is all labeled with a wire number and purpose, but some of the engine power wiring is not.

I have a feeling that the boat had electrical issues all along since the clean power CB had been replaced by a PO, but I think my testing has revealed that somewhere the power systems are connected. (plus it appears that the new alternator is defective).

I'll have to think about how best to go about finding the issue . . . probably going to look at the 2 alt/3 batt isolator next. Maybe take a look at the ProNautic charger wiring as well. All with the theory of that perhaps the things that are supposed to keep the engine power systems separate are not doing it.

 

[dubs283]

I'll have to think about how best to go about finding the issue . . .

You need to isolate systems/circuits

Start with a physical disconnection of all the batteries (not just turning off switches). Look at what leads provide power and ground for the stbd engine and that engine only. Reconnect the power/ground bypassing the battery switch. Look for issues.

Continue reconnecting items/leads until the issue presents itself again. It's a long, boring (for some) process that should include a known good dvm and the afore posted wiring diagrams. Don't skip steps or jump to conclusions or assume something is "okay". One circuit/connection at a time, in a row.

On a road trip you can't plan your fourth stop for gas while your still packing the car. You choose which pump you use as you pull into the station 12 hours later.

FYI I can't recall ever seeing a clean power circuit breaker. All known good clean power systems I've encountered have been connected directly to a battery. Not saying you have a clean power issue but clean power is part of all mercury systems since the advent of catalyzed engines, dts, axius, etc....ubiquitous these days. It's part of every system and not to be overlooked

 

[tpenfield]

Yes, if you drive on the CT stretch of I-95 or Rt-15, you don't have to worry about which gas stop, as there are service stations about every 15 miles.

Anyway, The labeling of the power is a bit confusing, and there are 3 leads that go to the starboard Pos isolation post. The 2 with CB's and a third, which turned out to be the clean power to the stbd engine.

The labeling of the 2 CB's is a bit interesting
'Merc Axius'
Main Pwr Relay
Axius Clean Pwr


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Neither of these actually put power to the clean power connector on the Stbd engine. It was the third wire that gave power to the clean power circuit (Red/Blk). In my testing, of connecting various power leads, I came to realize that the third lead was actually the Clean Pwr for the Stbd engine.

The clean power wire disappears into a harness, so I may have to pull more things apart to trace it.

Stbd engine '+' isolation post. (picture below)
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While most of the wiring is nicely marked along its length with a wire# and a description, these 3 wires had no markings.

So, I'm not sure what the difference would be from the engine's Clean Pwr and the 'Axius Clean Pwr' as labeled on the twin CB panel. Perhaps those feeds go to the smartcraft stuff at the helm? Not sure. . .

 

[dubs283]

The second picture is disgusting. Patination aside there's a lot going on, some of which we do not see on internet

Again....clean power is a thing, it exists and should be a trademark/colloquial part of any mercury product electrical troubleshooting regarding their products manufactured within the last ten years, no question. By design your setup is not experimental, strange, weird, off-putting or otherwise

And again, I'm not suggesting the clean power system is part of/the cause of your issue. Clean power is merely one of the earliest parts of proper mercury electrical troubleshooting you must verify.

Clean power needs to be connected directly to the main engine battery preferably with (probably required) an oem connection. You'll know it's oem with the factory battery ring terminal connections that has a spare 5 amp fuse located along the (+) lead inside a small plastic bag after the weather cap style main fuse connection

 

[tpenfield]

After a bit searching, I think I have come across what the clean power cable should look like. . .
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So, perhaps what I am seeing coming out of the wire bundle in the stbd electrical box (that looks disgusting) is the ring connector lead. Within the bundle, I should find the fuse holder. Not sure where the ground lead is connected, other than a (the) negative bus bar. I found the engine connector on both engines.

I'll have to see where the port engine clean power cable is located. The electrical wiring is much simpler on the port side of the boat.

 

[Scott Danforth]

I would order some wire, fuse holders and metripak connectors and make new runs or 2 of the cables and bypass the questionable wiring

You could be dealing with a damaged run (cross-talk), corrosion or other