port motor zinc trim tab eaten twice

[Solarman]

Have been ocean fishing ( 40-50 mile trip out) twice now in past month, and each trip my port motor has eaten the zinc trim tab, leaving a zinc ring just under the bolt. Oddly though my starboard motor tab doesn't look worn at all?
Have seen this happen on many motors, replaced many zinc tabs, but never understood this process.
I don't mind replacing the tabs, but if having some kind of electrical leak causing this, would like to correct if possible.
Any ideas how, or why this is happening would be helpful to know. Any way to test for this? Thnx

[BillCon]

I, have heard of that before and I, think your correct its a current leak usually happens to a boat in the water when the batteries are being charged because of the pos electrons acting as free radicals, as I, remember the charge coils also produce A/C current that can leak electrons before the rectifier converts it, my guess is there is a current leak somewhere.

[bassyac]

Google Seabis.com
A good site on electrical problems on boats
John

[Solarman]

Thnx for the replies.
Have investigated and found several bonding issues on my boat.so have corrected several that I've found. Will hope this corrects my issues. You have to watch out when contractors add fuel tanks, and aluminum T-tops to boats. All these items need to be bonded to the negative ground of the boat.
Thnx again.

[Drrnjns]

Why does one have to "ground"a T-Top? Out of curiosity, mind- before I install one,

Greets Dar.

[Solarman]

why bond a t-top

Mostly because of electrolysis. Another reason is generally people attach radar, GPS, and other antennas, or lights to it. If any one item goes bad it could cause an electrical bleed to the t-top, this will eventually cause an avenue for electrolysis.
In the water these reactions compound and start eating metals. It's always best to have all electrical & metals tied/ bonded to ground to eliminate as much deterioration as possible. Even metal fittings through the hull, and fuel tanks.
Good question, hope I answered it clear enough for you. Good luck.

[Drrnjns]

Does anyone have a decent wiring diagram for a 6m (20ft) poltester boat with rvs tank and outboard motor- or a "how to"?- I'm gonna give my boat a very thorough "once over" this winter..............

thanks again Dar.

[Solarman]

wiring diagram for boat

You ask for a wiring diagram? Every boat is different. Draw the shape of your boat, then itemize where all your metals are, then electronics. You have to remember that the negative post on your battery is your ground. If your motor is electric start, then you have a negative ground wire from battery already.
All of your electronics tie to ground also, but you should have a bonding wire that connects all the metals to the negative post as well.
Google, seabis.com. This and other sites like it will help to explain.
Can also google, boat electrolysis, and a number of sites with info will pop up.
Good luck, and I'm still learning allot of this stuff too.

[Solarman]

So, apparently my trim tabs are not being eaten by electrolysis. come to find out the vibrations have been breaking them off. Have gone through 5 tabs, 4 on my port motor, and the last time I went out I put the starboard tab on port motor. Port motor was the one this time with the tab. Starboard disappeared, less than 2 hrs running time.

I will not be installing according to manual.

[Moonlighter]

So, apparently my trim tabs are not being eaten by electrolysis. come to find out the vibrations have been breaking them off. Have gone through 5 tabs, 4 on my port motor, and the last time I went out I put the starboard tab on port motor. Port motor was the one this time with the tab. Starboard disappeared, less than 2 hrs running time.

I will not be installing according to manual.

Ok. Solution: buy one of those nice, smoothly running, quiet, smoke free, Suzuki 4 strokes!

[Solarman]

Ha ha, you wish. These 2 motors are doing well. As many problems that you seem to be having with the 4's, I think ill stick with simplicity. Too many extra moving parts, and too many extra dollars foe each.

Thanks Grant for the thoughts.