Fried Motor Grounding Wire

[h8mondays]

First off, sorry for the long post from a new guy, but I stumbled onto the board after searching for help topics and was hoping that someone would have some advice for me.<br /><br />Yesterday, I winterized my boat (2005 North River Seahawk - Honda BF150 and Yamaha T8). I pulled the batteries to hook them up to my battery tender in the garage for the winter. This all seems innocent, but I began backing the boat into the garage, but apparently I didn't lift the Honda up high enough and it drug/pushed on the ground for about 4-6 inches. I was more irritated with myself because it only scuffed up the paint and I now had to pull the cover and put a battery back in to lift the motor. It is a dual battery system with selector switch, so I put the #1 battery in and lifted the motor (no problems). When I backed the boat into the garage, I lowered the motor. It seemed like the tilt/trim motor was underpowered and it stuttered... that's when I noticed white smoke coming off the engine. I immediately shut down the battery switch and located the source of the smoke. There is a small grounding wire that connects the engine to stern bracket and the insulation was cooked. I have no clue as to why this happened and I pulled the battery to make sure nothing else was electrified.<br /><br />At this point, I'm scared to put the batteries back in and check it out, but at the same time, I want to figure this out and get it fixed while the boat is still under warranty. I don't know if only putting one of the batteries in vs. both of them was the problem. So, if anybody can help this boating newbie out, I'd be very appreciative.<br /><br />Thanks for any help

 

[rodbolt]

Re: Fried Motor Grounding Wire

you left an engine ground wire off something and the current was passing through the bonding wire as opposed to the engine ground cable.<br /> it happens. used to happen often on older 3 wire motor systems.<br /> I doubt very seriously its a warrenty claim.

 

[h8mondays]

Re: Fried Motor Grounding Wire

Other than not connecting the second battery, nothing else was disconnected. Could it have possibly been the second battery cables being grounded? Not sure if this would be the cause. <br /><br />Thanks for the reply though

 

[MajBach]

Re: Fried Motor Grounding Wire

rodbolt and h8mondays:<br /> I had almost the exact same experience - pushing boat in the garage, didnt lift it enough. When I went to lift the motor-it seemed sluggish and then i noticed the ground wire almost red hot. When I hooked the charger to the batteries - it worked fine. (My radio frequently drains the batteries id left sitting for a couple of weeks, hence the sluggish tilt). There were no connections altered prior or post the ground wire burning. <br />h8mondays: That was 4 years ago. I never changed the wire and I dont have any problems - I don't think it's serious as the connections to the frame are not insulated to begin with.

 

[rodbolt]

Re: Fried Motor Grounding Wire

that small bare wire is a BONDING wire. it is not designed to carry current. if it carries much it glows. its strictly to maintain a nuetral potention difference between various parts.<br /> if it glowed its trying to tell you someplace between the tilt motor and the - battery cable at the block there is a problem. we used to see more of it with the three wire motors that the tird wire was a ground, lose it and the bonding wire would attempt to carry about 30 amps, it cant do it.

 

[rodbolt]

Re: Fried Motor Grounding Wire

make that a potential difference

 

[h8mondays]

Re: Fried Motor Grounding Wire

Thanks for the info guys. I'm going to charge the batteries up and put them back in and mess with around with a multi-meter to see if the bonding wire is getting any juice. If it is, Ill run down the whole battery/electrical system.<br /><br />Thanks again<br /><br />h8

 

[MajBach]

Re: Fried Motor Grounding Wire

rodbolt: Your knowledge of the outboard design etc. obviously is warp 9 beyond mine. Despite my extensive electrical background, I cannot understand why current would be diverted through the 'bonding wire' just because the voltage is low...unless there is some type of solenoid somewhere in the loop. The only difference between the time I fried the bonding wire and the time where there was no problem was simply the state of charge of the battery. Actually, I have had several times since where attempting to lift the motor with seriously a drained battery and history does not seem to repeat itself. I just find it to be a very strange coincidence... identical motors, identical sysmptoms etc. Do you have any more thoughts?<br /><br />BTW, the definition of grounding is to eliminate electrical potential.

 

[rodbolt]

Re: Fried Motor Grounding Wire

bonding is eliminating potential differences, grounding is allowing a current path.<br /> thats why your not supposed to use a hulls bonding system for a current ground or battery negative path. a lot of folks do it but its not supposed to be done. next time ya jump on a big boat look for the green bonding wireing that bonds the hull fittings such as rudders,fuel tanks,shaft logs and through hulls and such. its a seperate circuit.<br /> why yours only did it once I dont know, its possible the honda you have is similar to some other designs that use the solinoids to complete the grounds and the low voltage failed to pull the contactor. but the stainless non isulated wires are strictly designed for corrosion protection not for a current path.<br /> we see a lot of fried bonding wires on twins if one of the engines ground wires fail. the other engine will usually try to complete the starting circuit through the tie bar,can lead to a host of issues. if you have a metal fuel tank look for a seperate bonding wire, same as if you have a metal fuel fill its supposed to be bonded to the hull electrical systems bonding. its not a current carrying circuit but a potential difference circuit. and hose clamping the bonding wire to the fuel fill is not accaptable even though I see it all the time. but if you have a metal tank look for a tab welded on the tank with a seperate circuit to ground and a green wire. some older hulls used white or yellow but BIA standards say its green now.<br /> on an outboard the swivel bracket and midsection are all mounted on rubber or nylon bushings, as it sits in the water the parts may lose electrical contact and start a galvanic corrosion process, the bonding wires prevent this electrical isolation and prevent on part of the motor from galvanically attacking another part of it.

 

[stealthiskey]

Recognizing last post here was 2005, but having experienced the same issue in 2018, Google brought me to this page, so maybe others are finding it too.

Have resolved the issue. The cause for that ground wire to get hot and smoke is as others have said - it's carrying current when it shouldn't be. Now the reason for that is because the trim motor has an internal short to the case. In my case it still functioned, but the extra current being shorted to case puts additional drain on the batteries, and reduces voltage available to the motor. Also found a clue to this last year - when attempting to raise/ lower while swimming, it would send a nice tickle through my arm.

 

[GA_Boater]

Recognizing last post here was 2005, but having experienced the same issue in 2018, Google brought me to this page, so maybe others are finding it too.

Have resolved the issue. The cause for that ground wire to get hot and smoke is as others have said - it's carrying current when it shouldn't be. Now the reason for that is because the trim motor has an internal short to the case. In my case it still functioned, but the extra current being shorted to case puts additional drain on the batteries, and reduces voltage available to the motor. Also found a clue to this last year - when attempting to raise/ lower while swimming, it would send a nice tickle through my arm.

So Google made you do it? Too bad Google didn't direct you to our rules!

Closed.