FX-1 what melted ,y ground cable

[whennotsailing]

Thoughts on a melted ground cable from battery to engine ? FX-1, went to crank it, turned a few times then i watched my ground go up in smoke after taking the hood off. Promptly ran for a screw driver and removed it from battery. Positive lead to the starter looks to be smoked pretty good too. To make matters worse, my engine seems to have a bad wrist pin.. thinking starter was working a bit too hard trying to turn the engine over ?

Is it possible for a bad/worn starter to cause a short like this regardless of engine issue ?

All connections were tight on both ends and corrosion free.

 

[Pro-pulsion]

Yep, if the starter has a bad terminal its only a matter of time before it shorts to ground. Similarly a weak battery and excessive cranking will create a meltdown between the brushes and armature. That would make a short to ground as well. I have seen the insulators on the high tension posts for the cables become loose. Then the cable gets space to wobble around while still being tight to the post, the post either internally or externally contacts the starter housing, immediate melt down. Its not the voltage that creates the heat, its the amperage. Nothing else on these skis creates the amperage that the starting circuit does so it should be easy to find the cause.

 

[JetManiac]

Yep, if the starter has a bad terminal its only a matter of time before it shorts to ground. Similarly a weak battery and excessive cranking will create a meltdown between the brushes and armature. That would make a short to ground as well. I have seen the insulators on the high tension posts for the cables become loose. Then the cable gets space to wobble around while still being tight to the post, the post either internally or externally contacts the starter housing, immediate melt down. Its not the voltage that creates the heat, its the amperage. Nothing else on these skis creates the amperage that the starting circuit does so it should be easy to find the cause.

Well said! Any short or poor connection in the starting circuit can cause this. Stuck, defective starter solenoid, bad cable in the middle of cables as well.

 

[speedysprocket]

Either straightup bad starter relay that got stuck, or the starter was bad and drew too much current or the engine was too hard to crank, caused the starter to draw too much, and all that current fused the relay together, continuing to short your battery...

 

[whennotsailing]

I'm led to believe it is starter overload that started this all, not sure what happened inside the motor yet, but turning it over at the coupling shaft proved to be very difficult. Will have to check out relay, (which was brand new mid summer). Couldn't a fuse be put inline of the relay to avoid it getting fused / stuck on ?

 

[Pro-pulsion]

If it is really difficult to turn over by the coupler you may have either water on top of one piston or too high of compression for even the starter to overcome, or there is a bent connecting rod as a result of trying to compress water. I hope its just compression for your sake =)

 

[whennotsailing]

Already took the head off, hard to turn without it on.... piston sloppy up and down like the wrist pin is toast. I'll know more when I take the jug off tonight and also check on the relay

 

[DAG]

And this is why we can't have nice things

 

[whennotsailing]

toasted. Rod bearing parted. piston ruined, cylinder needs help. Crank bearings all gritty too...

Rebuild crank and if so, how much and who ? Don't want to go sbt route.

 

[kswiatk]

@JetManiac should be able to sort you all out. Best in the business for parts!

 

[Philip Clemmons]

Any mechanical issue that causes slow cranking will cause significant current draw. Ohms law states the V=AxR. If you do the math (lol), you'll see that on a 12V system, the actual cranking current measured does not match what Ohms law says it should be based on the "measured" starter motor resistance. The reason, and key here, is that the resistance the starter motor actually sees (at proper cranking rpm) is a function of the "back EMF", or rapidly collapsing magnetic fields happening as the armature rotates. This adds the required resistance to control current flow in the circuit. If you slow or stall the motor, this "back EMF" is greatly reduced, or even non existent, and thus your current draw skyrockets. Measure the winding resistance on a starter motor and divide 12 by it. That's your potential current on a stalled motor.


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[BruceSki]

I've got a full 62t engine if you are interested.

$400 plus actual shipping