excessive corrosion?

[jlh3rd]

would this be considered excessive. Its on a new merc 115 i stalled july,2021. Used only on a river and two fresh lakes. It does sit in the water all season , motor up...
the other anode is clean..
Never really saw it on the orig.60 hp the last 3 years prior...

 

[flashback]

would this be considered excessive. Its on a new merc 115 i stalled july,2021. Used only on a river and two fresh lakes. It does sit in the water all season , motor up...
the other anode is clean..
Never really saw it on the orig.60 hp the last 3 years prior...

Can't see it. Stray shore current does eat them.

 

[jlh3rd]

Can't see it. Stray shore current does eat them.

sorry, here

 

[QBhoy]

Is that the anode ? If so…I’d say it’s excessive. I’ve the same engine and it’s sits in the water for 8 months if the year, for last 3 years. Mine isn’t that bad. Is it in a marina with shore power ? Is there earthing issues if so ? Any other electrical interference locally to it ?
Even with my stainless prop on..not that bad.
I’d also say that these are meant to be changed at 300 hours as a schedule…but looks excessive to me. Have a look around you for anything that may be accelerating things.

 

[flashback]

Been in fresh water for a year and a half, It's doing the job it was designed for. I would replace it with a magnesium.and see how that works for you.

 

[QBhoy]

Been in fresh water for a year and a half, It's doing the job it was designed for. I would replace it with a magnesium.and see how that works for you.

Definitely agree with the change to magnesium. But still think given it’s likely the aluminium standard new fit…and comparing directly to mine with more exposure…there is something going on there. Suspect there is an external influence going on there.

 

[jlh3rd]

thanks...yeah....
so the pontoon it's on sits in a slip in a little inlet type place/campground on a river.
There are no electrical hookups for boats. There are hookups for the campers....I have no electrical issues with my boat.
There are three total anodes, here's one of the other ones. The one in the cavitation plate is clean also.....they're aluminum .....came with the new motor.......
the boat has been moored there during the season for the last 5+ years. Stored on trailer during off season...... never saw anything like this with the original 60hp motor....

 

[jlh3rd]

older google earth pic...but there's the inlet..

 

[dingbat]

thanks...yeah....
so the pontoon it's on sits in a slip in a little inlet type place/campground on a river.
There are no electrical hookups for boats. There are hookups for the campers....I have no electrical issues with my boat.

That you know of at the moment.

Where does that bonding wire shown in the picture terminate?

First, check for continuity between all three of anodes to make sure they’re functioning as one to dissipate any current presented.

Ideally, you would want to run the following tests while the boat is in the water but it can be done on land as well by sticking the ground probe in the dirt

Check for voltage between the corroded anode and water (earth ground) then measure between corroded anode and battery ground.

Anything other than 0.0 volts on either measurement is a problem.

 

[jlh3rd]

I'll go see where that strap terminates...
will do those tests.....thanks...

 

[airshot]

Magnesium erodes faster than aluminum, but that means it will protect better even though you will need to replace it more often. If you cant find an electrical issue, I would switch to magnesium electrodes to save the rest of your stuff from erosion....these anodes are much cheaper than replacing your pontoons or motor !!

 

[QBhoy]

It’s ohms you want to have it set to really

 

[jlh3rd]

the strap terminates upwards and can't be seen....
readings, dc v, negative lead stuck in ground, are:

-320 mv's from anode bar to ground. ( yes,negative). The same for a transom mounting bolt head to ground.
I have continuity between all anodes, all grounded bolts to anodes ...and to the toons.....
O volts between anode and a grounded bolt.
I don't have acess to a battery ground wire...boat is up for the winter..battery master switch "off" ...battery disconnect "off"...
I cleaned up the anode bar......it doesn't look deeply pitted anywhere.....
?'s...comments?

 

[jlh3rd]

It’s ohms you want to have it set to really

oh...eh....ok...I'll run back out

 

[flashback]

I think the voltage check was to rule out stray current generated by the boat. In any case the anode doesn't appear to have lost much.

 

[jlh3rd]

ohm readings:
anode to earth....36.8 K ohm
toon to earth........36.8 K ohm
anode to anode.....0.7 ohm....

 

[QBhoy]

ohm readings:
anode to earth....36.8 K ohm
toon to earth........36.8 K ohm
anode to anode.....0.7 ohm....

As long as the continuity (ohms reading) between what’s supposed to be adjoining and protected, is close to zero….should be good.
Flashback above and previous post around voltage perhaps relevant too. Apologies if I confused things earlier.

 

[flashback]

If the battery is disconnected/switched off then the v check is moot, My bad

 

[dingbat]

-320 mv's from anode bar to ground. ( yes,negative). The same for a transom mounting bolt head to ground.

If you swapped leads it would be + 320mV

It looks like you found your problem.
Now all you have to do is find where the 320 mV is coming from. I suspect something is improperly grounded.
Anything wired directly to the motor?

If the battery is disconnected/switched off then the v check is moot, My bad

Why is that?
The idea of the exercise to eliminate stray current as the culprit. He found 320mV to ground (earth) with the power off.

Ideally you would want to check the same point to the battery post to eliminate the possibility of the charge coming from ground

 

[jlh3rd]

I think the voltage check was to rule out stray current generated by the boat. In any case the anode doesn't appear to have lost much.

I didn't think so...
I

If you swapped leads it would be + 320mV

It looks like you found your problem.
Now all you have to do is find where the 320 mV is coming from. I suspect something is improperly grounded.
Anything wired directly to the motor?


Why is that?
The idea of the exercise to eliminate stray current as the culprit. He found 320mV to ground (earth) with the power off.

Ideally you would want to check the same point to the battery post to eliminate the possibility of the charge coming from ground

pos/neg...yeah, i understand, was just posting in case it made some difference to those offering help.

so..brief history. No electrical problem ever after obtaining this '06 pontoon around 2017 ish. Simple electrics. One battery, Horn, dock, nav, stern lights, depth finder, stereo, engine instruments...Factory rats nest however....
winter/spring 2021 I added a separate stereo switch and a battery master switch to feed said components. Added a ground buss bar and a power buss bar under the console...all mounted on plastic ...an extra battery with selector switch and and a sensor thats selects which battery needs charging.....all mounting on a 1/4 inch plastic panel mounted to the alum. rail in the engine compt.
the new motor is all factory..."wired"...
....so..how do i find this 320 leaking mv's
I don't have and never had dead battery issues.....
um...two solar chargers mounted on back....