electrical problems please help

[sbennett139]

I have a 70's Suzue 18hp tractor. It has a mitsubishi k3d diesel engine. Well sadly the battery charger/jumper was hooked up backwards a short while later there was a pop and a bit of smoke the error was realized and charger removed and the tractor was dead in the water. The tractor now has a new battery. I assumed either a fusable link or a fuse blew. I only found one 15amp fuse it has been repplaced and a new battery was put in the tractor. The dash lights won't light and the engine does not turn over. I do know I have power to the starter but have not traced it any further. Any and all recommendations are welcome. Thank you all!

 

[JerryK]

You could unhook your new battery and ring [ check for continuity with an ohm meter ] out the large wire going from the battery to the starter, and also any other large wire either leaving the positive battery terminal, or from the starter. Those are the wires that USUALLY contain the fuseable links. USUALLY the links are just a slight bulge in the wire, sometimes covered with shrink wrap insulation. Would be a quick test. You should read very little resistance in these wires. Also ring out the negetive battery lug to the frame to make sure that side is good. You also could have injured a connection between the wire and the battery connector, but I doubt it... Good luck, Jerry

 

[the old grind]

Fella I bought my JD from had reversed cables too, and the alternator was fried in an instant. If yours went South as well it may take out something else. While you're checking wires for continuity make sure none has shorted to ground, too. Here's hoping you'll only have to replace a fuse or link. Let us know how it goes ...

 

[sbennett139]

Well after a little time actually tracing wires I found the the broken fusable link! Almost too good to be true. I want to replace this with a fuse what size and type would be appropriate?

 

[JerryK]

The fuseable link is a safety of last resort... it is designed to blow open before your wiring melts/tractor goes up in smoke. It should be able to carry the max current your battery can put out for a certain amount of time. It also protects the wiring, but automotive wiring is rated completely different than house wiring... without much safety consideration. You would be better off trying to get the wire/with link from your dealer. Or, you may find something at an automotive parts place that would work. Last option, which I would not do, is not use a fuseable link, and just wire direct.
But really, if the link you blew was in the starter wire, you need a big fuse... several hundred amps or more... depending on battery size. If the link you blew was in the wire going to the key switch... you could probably go with 20 amps or so.... start low, and work up to a bigger fuse if needed...

 

[sbennett139]

Jerryk thanks for info. The link was from the starter to the ignition. So my thought was it would be ok to use a fuse. Going to the dealer probably is a no go being that this is a grey market tractor. I suppose looking at the auto parts store for a link wouldn't be a bad idea. Looks to be 16 gauge wire so if I went the fuse rout I would start at 12amp fuse. As far as electrical components there are a few small dash lights head lights blinkers and that's it. Any thoughts?

 

[crazyal]

Do you know how much wattage the headlights are? If so you can probably add up everything and get an idea of how much current could be going through the fuse. Does the engine have a mechanical shut off for the fuel? Also the starter get's it's main power directly from the battery but it will still draw a little current from the switch. All of that will need to be added up. Also if the fusible link was a time delay type a standard fuse may not work.

Unlike household wiring "rule of thumb" in the auto world the length of the wire is also needed when trying to identify the maximum amount of current it can carry. I think I would go to a place like Autozone and see what they have for fusible links. Most Japanese cars use a style that plugs in so it shouldn't be too hard to adapt one. I would start off no higher than 15 amps, might be too small to find at a car parts store.

 

[JerryK]

Ditto on the 15 or 20 amp fuse thing for that wire ... If it looks like a #16 wire... it is probably a #10 automotive wire... It is scarry how they rate stuff..... Automotive Wire Information - sponsored by Allied Wire & Cable, Inc. Sort of " well, it doesn't glow red or melt, so, that's big enough .... "

 

[the old grind]

Any fuse must be sized for the wire it protects, stranded or solid. When in doubt as to gauge, look for 'xxAWG' printed on the insulation. Compare unmarked to marked of similar type/size.

Fusible links are good for service/towing biz. Never regretted replacing one with std wire & an in-line fuse holder ...

 

[crazyal]

I've seen this chart all over but I have no idea where it originated from.