Ground Wire/Strap on Lower Bracket

**Basnova** · 08-09-2020, 01:19 AM

Not exactly sure what it's called, but I am trying to find out what part number I need for a ground wire that is bolted to the port side big nut that inserts into my Lock 'n' Stow bracket. I've checked diagrams on sites like Crowley but can't tell which one is which. I did come across this, though, which looks like it might work, but I can't confirm the application for my 1998 Promax 300. Any help would be appreciated.

http://www.boats.net/product/mercury...hoCFGQQAvD_BwE

**keefallan** · 08-09-2020, 04:45 AM

I am not a merc guy. You can use that strap if you compare it to your old one. Use the ruler provided to compare sizes with the old strap. And you can always enlarge the smaller hole with a drill bit if necessary. But I am sure someone here will give you the part number needed.

**Basnova** · 08-09-2020, 11:17 AM

Thank you for the tip. I took mine off and measured it, and it looks like the correct part. The outer edge of the large ring on mine broke near where the wire connects to it. The wire is still connected to the broken piece of the ring, and the ring is still a complete circle. Do you think soldering the ring back together would be OK, in the meantime while I order the part?

**keefallan** · 08-09-2020, 11:31 AM

If you can get the solder to hold, go for it. If not, make a new one with copper wire and ring terms. Its only temp and it will work just fine.

**Basnova** · 08-09-2020, 07:15 PM

I'm not sure what kind of metal the stock terminal ring is, but when I tried to solder it, when it heated up it only sucked the Flux out of the solder, but never took the solder.

Since the break was at the ring, I still had all the cable length, so I cut the broken piece of the ring off the cable, and crimped on a standard automotive terminal ring I happened to have in my garage. It's almost the exact same size as the original, and fit on the large bolt just fine. But, should I be using a ring made of some particular type of metal for something that will see a lot of water when I take the boat out? If it matters, it's a bass boat that sees mainly freshwater lakes, with periodic trips to brackish water, and when not in use the boat is kept in my garage. If it's OK to use a standard terminal ring in this application, I won't even need to order that cable.

Thanks again.

**keefallan** · 08-10-2020, 03:27 AM

THat terminal is stainless. The bottom line is that you can either buy a stainless ring term or not. That automotive will corrode over time.....its got copper in it. I would also get a crimper designated for non insulated crimps if you dont already have one. They make a much better and complete crimp.

**rgsauger** · 08-11-2020, 09:03 AM

Doesn't this ground strap only matter if your boat is stored in the water with motor submerged? If stored dry, does it serve a purpose?

**Fishinmymission** · 08-11-2020, 11:47 AM

Interesting story i had this wire corrode out and all my zincs when checked also corroded to the point of not being in contact. Noticed my entire lower unit (it was an SEI) had aluminum oxide galvanic blisters all under and cracking the paint. Boat sits in saltwater and just the nose tip of the motor contacts the water when trimmed up. Interesting how only the SEI lower blistered and the stock mercury exhaust housing was fine. Mercury must use a higher galvanic potential aluminum and the SEI lower housing became the next sacrificial anode.
Also quickly crimped in a solid copper wire while waiting for the mercury part. Cant use solid wire it will quickly fatigue crack with the turning motion and vibration.

**keefallan** · 08-11-2020, 03:58 PM

Originally Posted by rgsauger

Doesn't this ground strap only matter if your boat is stored in the water with motor submerged? If stored dry, does it serve a purpose?

Electrolysis prevention or the slowing of it.

So, it may not serve a purpose(in the way you are asking), but it may still help. There is always electrolysis going on..........motor running, battery charging.etc......worse in saltwater obviously.

**Chaz** · 08-12-2020, 10:17 PM

Originally Posted by keefallan

Electrolysis prevention or the slowing of it.

So, it may not serve a purpose(in the way you are asking), but it may still help. There is always electrolysis going on..........motor running, battery charging.etc......worse in saltwater obviously.

Man .. no wonder …

I been chargin the whole ocean …

This one here was runnin the bottom cylinder as a hydrogen / oxygen converter ..

**keefallan** · 08-13-2020, 02:19 PM

How long did that take Chaz? Thats a nasty one................

**Basnova** · 08-17-2020, 08:36 PM

Originally Posted by Chaz

Man .. no wonder …

I been chargin the whole ocean …

This one here was runnin the bottom cylinder as a hydrogen / oxygen converter ..

Wow!

**Basnova** · 08-17-2020, 08:39 PM

Originally Posted by keefallan

Electrolysis prevention or the slowing of it.

So, it may not serve a purpose(in the way you are asking), but it may still help. There is always electrolysis going on..........motor running, battery charging.etc......worse in saltwater obviously.

I, too, thought it only mattered in saltwater, where I heard that two different metals in saltwater automatically form a battery of sorts. Although these days my boat only sees brackish water twice a year at most, and is not stored in any water when not in use, I don't want to take any chances. Am I wrong here?

**Chaz** · 08-18-2020, 11:08 AM

It is an Opti block. They seem to rot worse than carb or EFI models. Not sure if the energy required to run the fuel/air system has anything to do with it or not.
It's not mine, it was plopped on my floor .. fix it .. I did , broken bolts and all ..

**keefallan** · 08-18-2020, 01:55 PM

Here's the deal...........stainless and aluminum hate each other. Add water...........problems. They are dissimilar metals. You are gonna have problems. Most people dont realize this..........."its a freshwater motor" Blah, blah,blah..........

It does help that it was a freshwater only motor. But I just removed a powerhead from a midsection. Almost every bolt was seized in the adapter. Galvanic action was the enemy here. I am just making my case of the two metals not liking to be mated together.

Anything you can do to keep that from happening is good.......proper grounds(or jumpers in flexible situations)and even anti seize. I hate to say it, but there is still salt in brackish waters. Not as bad as salt, but still much worse than fresh. I know, I am a brackish guy myself.

There is electrolysis in any water............just an fyi. If your motor is running..........battery hooked up.....etc.........there's stuff going on. Its our job to minimize it.