wiring harness corrosion.

[RichardB]

Last Tuesday I took my wife and four of her visiting relatives including 15 and a 5 year boys from Portland out for a day of boating. It was a spectacular day, culminated by their first snorkeling experience. Took them to Peanut Island, just facing the Lake Worth inlet (Port of Palm Beach, FL) at high tide when the water is turquoise and clear. The 15 year old was first in the water and donned a mask for the first time, and after taking one look underwater started yelling excitedly about all the amazing fish he could see. So my wife handed him my dive camera and the very first picture he takes is of a manatee under the boat. No kidding. I dive/snorkel quite often and never had this photo opportunity except at a 'swim with the manatees' cruise near the west coast (that means Tampa area here). Any how as you know from the subject line that's not the story I'm here to tell. After this great relative-pleasing outing, I parked the boat as usual in the back yard and proceeded to do the fresh water flush but the 2006 Honda BF50A motor would not turn over.
* Found the 10A fuse blown (15A cranking fuse is fine)
* Replaced it, it immediately blew again.
* Unplugged the ignition switch from the harness.
* Unplugged the kill switch from both the harness.
* Replaced fuse - OK. power tilt working.
* Plugged in the kill switch to the harness with the lanyard/plastic key on - fuse still OK.
* Removed the plastic key - fuse blew immediately.

What a nasty surprise that would have been if this had happened earlier that day!

Baffled, I got some help from another engine specific forum, MarineEngine.com, you can find the full thread in the Honda outboard section, but to make a long story short: the problem turned out to be corrosion in the wiring harness that transmitted 12v to the line that kills the motor (short from white/black to black/red), and when this line was grounded (as when switch is off) it blew the fuse. Apparently the harness was improperly prepared when I bought the boat new in 2006, allowing salt water to enter and contact bare metal.

One foot away from the engine is a three wire cable with connector, I assume for trim controls which are not needed on our boats. This looked like the most likely trouble spot so decided to start there and opened it up. It looks like whoever prepped this cable ~4.5 years ago made a clumsy round cut with a sharp knife straight into the cable to open the sheath, slicing to the metal in the outermost wires. Afterwards he covered it up nicely with the heat shrink sleeve so from the outside the harness looked perfect. But it obviously allowed salt water intrusion inside, and over time it gradually became the corroded mess now I see inside. Maybe the bending from raising the motor the last time finally caused the hard short that is obvious between the white/black (12v) to the gray wire. I separated all wires and made temp repairs with electrical tape and crimp connectors. Rechecked all pins and no more shorts. Engine started and ran smoothly.

Now I need to do a permanent repair, which I suppose will be to replace the entire cable. Unless, I can somehow obtain 14 replacement pins for the big round connector, the ones with the integral black seals, and then I could rebuild that end after cutting off the problem section. There is ~10' of spare cable coiled in the bilge so it's a shame to have to buy a new one if I cannot find the pins.

Richard

[DaveB]

Richard, once mosture gets in the cables and leads to a short in the wire ,chances are you need to replace the cable as water can go a long way inside the cable and mosture will do rest of damage.
I would replace Cable.
I had a short in one of my Elect. Golf carts 4 gauge wire 2 days ago, I replaced all the cables in the 36 volt system but one cable end was not sealed and completly separated on the wire to terminal by electrolis and battery acid.(thats what caused to failure).
I use heat termole connectors on all my wires and often solder them but if a factory built cable fails because of faulty connection and seals than it's there fault because you rely on a sealed unit.
I often don't trust them and use liquid tape that does seal from mosture as a backup.
Dave

Last Tuesday I took my wife and four of her visiting relatives including 15 and a 5 year boys from Portland out for a day of boating. It was a spectacular day, culminated by their first snorkeling experience. Took them to Peanut Island, just facing the Lake Worth inlet (Port of Palm Beach, FL) at high tide when the water is turquoise and clear. The 15 year old was first in the water and donned a mask for the first time, and after taking one look underwater started yelling excitedly about all the amazing fish he could see. So my wife handed him my dive camera and the very first picture he takes is of a manatee under the boat. No kidding. I dive/snorkel quite often and never had this photo opportunity except at a 'swim with the manatees' cruise near the west coast (that means Tampa area here). Any how as you know from the subject line that's not the story I'm here to tell. After this great relative-pleasing outing, I parked the boat as usual in the back yard and proceeded to do the fresh water flush but the 2006 Honda BF50A motor would not turn over.
* Found the 10A fuse blown (15A cranking fuse is fine)
* Replaced it, it immediately blew again.
* Unplugged the ignition switch from the harness.
* Unplugged the kill switch from both the harness.
* Replaced fuse - OK. power tilt working.
* Plugged in the kill switch to the harness with the lanyard/plastic key on - fuse still OK.
* Removed the plastic key - fuse blew immediately.

What a nasty surprise that would have been if this had happened earlier that day!

Baffled, I got some help from another engine specific forum, MarineEngine.com, you can find the full thread in the Honda outboard section, but to make a long story short: the problem turned out to be corrosion in the wiring harness that transmitted 12v to the line that kills the motor (short from white/black to black/red), and when this line was grounded (as when switch is off) it blew the fuse. Apparently the harness was improperly prepared when I bought the boat new in 2006, allowing salt water to enter and contact bare metal.

One foot away from the engine is a three wire cable with connector, I assume for trim controls which are not needed on our boats. This looked like the most likely trouble spot so decided to start there and opened it up. It looks like whoever prepped this cable ~4.5 years ago made a clumsy round cut with a sharp knife straight into the cable to open the sheath, slicing to the metal in the outermost wires. Afterwards he covered it up nicely with the heat shrink sleeve so from the outside the harness looked perfect. But it obviously allowed salt water intrusion inside, and over time it gradually became the corroded mess now I see inside. Maybe the bending from raising the motor the last time finally caused the hard short that is obvious between the white/black (12v) to the gray wire. I separated all wires and made temp repairs with electrical tape and crimp connectors. Rechecked all pins and no more shorts. Engine started and ran smoothly.

Now I need to do a permanent repair, which I suppose will be to replace the entire cable. Unless, I can somehow obtain 14 replacement pins for the big round connector, the ones with the integral black seals, and then I could rebuild that end after cutting off the problem section. There is ~10' of spare cable coiled in the bilge so it's a shame to have to buy a new one if I cannot find the pins.

Richard

[RichardB]

Thanks Dave, I suppose water can travel a long ways by capillary action. But I'm going to chop 10' off the harness and rebuild the connector, I just ordered the pins and seals from the honda dealer. Replacing it would remove all doubt, but the harness is quite expensive and money is tight now. I'll be check the pins for corrosion periodically, at oil changes.

Richard

[DaveB]

Richard, you may want to use liquid tape to seal even factory connections and works great on all your other elect. connections.
Dave

Thanks Dave, I suppose water can travel a long ways by capillary action. But I'm going to chop 10' off the harness and rebuild the connector, I just ordered the pins and seals from the honda dealer. Replacing it would remove all doubt, but the harness is quite expensive and money is tight now. I'll be check the pins for corrosion periodically, at oil changes.

Richard

[Hamin' X]

A suggestion on using the liquid tape. Wrap a layer of real vinyl tape around the connector first, then coat with the liquid tape and extend past the edges of the tape. This will prevent migration of the liquid into the connector and much expedite removal in the future.

~Rich