new to me mc crawler

[monzanick]

So my crawler is 150 miles away under some tarps. its been there for 10 years. I went up there, unearthed it an tried to start it.

so my questions are : what direction does the engine turn over? I thought these were pos ground but the cables fit the other way... i hooked it up pos ground an it spins over o/k but no spark... i've isolated that to a bad coil which i'll install on my next trip up.

Are there any wiring diagrams out there?

if you change over to 12v ya gotta go wit neg ground right? won't the starter spin the wrong way?

I fix cars for a living but this is throwing me a bit.

Thanks all!

[Lavoy]

Starter spins the same way regardless of polarity or voltage, so don't worry about that. Check your points, that would be my first guess.
Lavoy

[LarryD]

The starter will spin the same direction on either voltage, and regardless of polarity of the cables. Without getting too technical......I hope..... the only way to make one spin backwards would be to change the polarity of the field windings internally in relation to the armature. But anyway the short answer is that it isn't spinning backwards. I also agree with Lavoy, most likely culprit causing no spark is points.....second would be condenser. Hope this helps.

Larry

[shinnery]

The only time you have to worry about the polarity of the battery is if you have an alternator. The diodes in an alternator determine which polarity you need to connect to ground. Over 99.9% of automotive alternators are designed for negative ground. Starters don't care which polarity, they will spin the same direction by their internal construction. Generators don't care, the regulator must be polarized when first used to be able to charge a battery. Normally the coil should be connected the same terminal to the distributor as what battery ground is. It will work wired either way, it just works a little better wired the same way. The ammeter just senses current and you want it to move in the positive direction when the generator/alternator is charging the battery.
Bryce

[gregjo1948]

If it were me, I'd use a 12 volt battery to crank it up. If your worried about the generator, just unhook it until; you get it home. It will crank much better and start up quicker. Don't crank it for long periods. The points and condenser will take the voltage a long time. If you convert the whole machine to 12 volt, you can probably go with a pointless ignition. Hope this helps.

[LarryD]

The only time you have to worry about the polarity of the battery is if you have an alternator. The diodes in an alternator determine which polarity you need to connect to ground. Over 99.9% of automotive alternators are designed for negative ground. Starters don't care which polarity, they will spin the same direction by their internal construction. Generators don't care, the regulator must be polarized when first used to be able to charge a battery. Normally the coil should be connected the same terminal to the distributor as what battery ground is. It will work wired either way, it just works a little better wired the same way. The ammeter just senses current and you want it to move in the positive direction when the generator/alternator is charging the battery.
Bryce

Not trying to be a know it all, but don't want someone to be misinformed and think that they have bought a bad generator right out of the box. I believe you have it backwards. The regulator doesn't care about polarity, as it is just a magnetic relay.....The generator does care though and must have the fields polarized. The term used years ago was "Flashing the field". By flashing the fields it leaves a little bit of residual magnetism which essentially "tells" the generator what its direction it should charge. I imagine the confusion is created in the fact that you flash the fields at the field wire of the regulator.

[monzanick]

I had pulled off the cap an rotor, the points looked o/k. with ignition on the points sparked a bit. i swapped out the condensor for a known good one, checked power and ground @ coil but no spark. tried swapping in an old small block chev but that one had broken nuts so i couldn't use it.

I ordered new cap/rotor points/condensor wires an plugs. i figgure its been at least 10 years from it being running. an who knows how long its been since a tune up.
one of the spark plugs had broken ceramic @ the top and was a ALDOR brand. I never even heard 'o them.

Here's hoping that this thing will fire up an drive on the trailer and away from my bumbling uncles.

[hydrogeo]

FWIW, my 40c would barely run when I got it. New cap, rotor, wires, points and plugs and it now starts and runs better than anything else in my "fleet".

[Willyr]

You didnt tell us if you had checked for compression.

[LarryD]

Here's hoping that this thing will fire up an drive on the trailer and away from my bumbling uncles.

Hmmm, seems I have an uncle just like that.....loveable, but sure can lead you down a long crooked path with their "wisdom".

[monzanick]

well the only way I had to check compression was with my thumb over plug hole. it went "phhhhhttttt" and pushed my thumb away. yep reallly accurate huh?

[Lavoy]

All depends on how accurate your thumb is!
Lavoy

[monzanick]

Put coil, cap,rotor,wires,points hit the starter an it popped off an ran like a top! it moved, grooved and the bucket even worked well. wooo hooo!!!!!