melted wires on digger - why?

have2flushtwice

I have a case cx36, 3 tonne, and it wasn't started for a few months.
I went to use it on Saturday and ran into some problems. firstly it wouldn't crank, good battery, etc but the starter was silent. there was power coming from the battery, and from the ignition signal switch when the key was in the position where it should try to start. so I removed the starter, checked it on the bench and it worked after a few goes.. the switch inside must have been stuck. I replaced the starter and it cranked over.
but it didn't fire.
so I tried a few times, and saw some smoke.....
I took the battery out asap and started to look it over. the wire from the battery to the ignition had melted through, it must have been red hot.
why would this happen?
was the ignition drawing too much current?
someone told me there are resistors in the ignition which can go and this may be the cause of the melted wire. I know there were some fuses removed and a bolt inserted instead. this defeats the purpose of the fuse box. however, I dint know what fuse would withstand th e melting the wire took, so I need to troubleshoot the melting problem before I replace the fuses.

kay 9

Must be a short somewhere. If there was a fuse installed the wires shouldn't have melted. I'd change the bolts to fuses first and work from there. Whatever kind of a jack dick put bolts in instead of fuses ffs. You're lucky the machine didn't go up in smoke. It's more common than people think. Worth putting an isolator on the battery to add extra precaution.

have2flushtwice

I got a roll of wire today and a fusebox, goin to replace the burnt wire and fuse it.

Tail Docker

have2flushtwice wrote: »

I got a roll of wire today and a fusebox, goin to replace the burnt wire and fuse it.

Make sure the starter isn't shorting internally/seized - run it with jump leads to test.

have2flushtwice

Tail Docker wrote: »

Make sure the starter isn't shorting internally/seized - run it with jump leads to test.

I took out the starter and ran it with he leads and battery, it turned freely by hand, but did not rotate the first time I put the leads onto it. took a few go's, and then it ran fine.

Tail Docker

have2flushtwice wrote: »

I took out the starter and ran it with he leads and battery, it turned freely by hand, but did not rotate the first time I put the leads onto it. took a few go's, and then it ran fine.

Was probably a slightly seized solenoid - I'd also be having a look at all the terminals along the route and brighting them with some emery paper. Check for breaks in the cable insulation shorting too.

sandydan

Tail Docker wrote: »

Was probably a slightly seized solenoid - I'd also be having a look at all the terminals along the route and brighting them with some emery paper. Check for breaks in the cable insulation shorting too.

+1 for that , as well id check route of cable,in case insulation dug into by a metal part occasionally don't know anything about Case but had similar experince with tractor.
bolts are used by some occasionally as fuses. milking machine tech went to fella who couldn't cool milk.checked fuses and found one eight bolt in stead of fuse on old type fuseboard . farmer told him twas the only thing to cure blowing fuses bleddy nuisance weak things, id say he was lucky to be alive,cable was immersed in water.

have2flushtwice

I'm after replacing the wire from the battery to the ignition (which was the wire that was burnt out) with a heavier wire, and I fused it also, its working perfect. new battery and it starts in about 3 seconds.

so between a bad battery which was not cranking fast enough, and a poor wire, that was the problems. I think the wire, which was a single heavy core, was not able for the amps coming through it. may have been electrical wire which would have been probably <13 amps.
there is a 25 amp fuse in now, and that's not blowing.

sandydan

have2flushtwice wrote: »

I'm after replacing the wire from the battery to the ignition (which was the wire that was burnt out) with a heavier wire, and I fused it also, its working perfect. new battery and it starts in about 3 seconds.

so between a bad battery which was not cranking fast enough, and a poor wire, that was the problems. I think the wire, which was a single heavy core, was not able for the amps coming through it. may have been electrical wire which would have been probably <13 amps.
there is a 25 amp fuse in now, and that's not blowing.

well done , is there a recomended fuse strength loading for that wiring i wonder , im thinking of replacing wire and battery leads in MF 399 as they arent taking battery voltage to starter ,also the wire from switch to solenied has been cracked and joiner strip used with half roll of tape around it.
what is the essential difference between auto and house electric wiring i think the difference apart from load is in outer casing( but as usual i may be wrong), similar to wiring used in sheds etc (they use some letters to describe it ,is it WYMJ or similar).seldom for wire between starter switch and battery to give trouble like that unless chafed and earthing, as its heavy as rule.
had melting experience with tractor i purchased once only it was electrical wire installed to heater unit in Ford 5000 fitted with 6600 engine.correct cable for heater got lost during engine switchover ,so electrical wire was used and in melting it ignited the stupid dsl pipe used as return to tank. lucky for me when it happened a chap was washing a wall and i used his bucket of dirty mucky water,far better than clean water imo

Mech1

Check your earths too, in the old days many a choke cable was the only good earth left causing fires on startup.

Tail Docker

Mech1 wrote: »

Check your earths too, in the old days many a choke cable was the only good earth left causing fires on startup.

On almost every machine, it's worth running a new, extra earth from an engine bolt to the main chassis - a good, strong earth strap. An awful lot of bad starting/flattened batteries/fires are caused by crappy earths - the Cat 428s used to be notorious for it.