1955 international 300 utility w/front loader

[MacAR]

Personally, I'd tear all that out and start over. Here's the diagram I used on my H:

Pretty simple to figure out, but for a one wire setup you'd eliminate the two smaller wires from the alternator and the warning light from the system. I had to use the three wire setup because the H doesn't turn fast enough to self excite; your 300 might not either so just be aware of that if it doesn't charge. 

Mac

[Tyler Fontes]

16 hours ago, snoshoe said:

Normally I would tell you to move the gen or arm wire (depending on how it's labeled) onto the bat terminal along with the wire that is already there. From the looks of it you might be better of just butt connecting together. Then at the alternator just connect the blue wire to the bat terminal. Then if it hasn't been done wires at ammeter and ignition coil need polarity swapped. If that alternator is much over 42 amp. There is a real danger of smoking the wires. Several solutions for that. The problem of a belt that will tighten and alternator fit under hood I leave to you.

What do u mean by polarity swapped? Yes the alternator is a 100amp alternator!

[snoshoe]

23 minutes ago, Tyler Fontes said:

What do u mean by polarity swapped? Yes the alternator is a 100amp alternator!

Those were positive ground. The alternator requires negative. Don't know what it's present status is. Yes you need bigger wire for that alternator. Personally wouldn't use it. To hard on belts and totally unnecessary. 

[MacAR]

1 hour ago, snoshoe said:

Those were positive ground. The alternator requires negative. Don't know what it's present status is. Yes you need bigger wire for that alternator. Personally wouldn't use it. To hard on belts and totally unnecessary. 

I agree. A standard Delco 10SI alternator is just fine for this. Absolutely no need for anything bigger. 

Mac

[Matt Kirsch]

Looks like a Delco 10SI alternator to me.

Just because it's "100 Amps" does not mean it is generating 100 Amps of current constantly. It only creates enough current to maintain regulated voltage. That could be as little as zero Amps.

The only time the alternator would put out anywhere near 100 Amps is if there were a 100 Amp load on it. Even a flat dead battery doesn't put that much of a load on the alternator. My bet is it's not even capable of producing 100 Amps. Those claims tend to be inflated.

[snoshoe]

46 minutes ago, Matt Kirsch said:

Looks like a Delco 10SI alternator to me.

Just because it's "100 Amps" does not mean it is generating 100 Amps of current constantly. It only creates enough current to maintain regulated voltage. That could be as little as zero Amps.

The only time the alternator would put out anywhere near 100 Amps is if there were a 100 Amp load on it. Even a flat dead battery doesn't put that much of a load on the alternator. My bet is it's not even capable of producing 100 Amps. Those claims tend to be inflated.

My experience says that a half discharged right after cranking is going to draw right around 60 amps. Pushing that much through a 12 or even a 10 gauge wire is just asking for smoke. That doesn't include the squealing belts. A single 1/2" belt seems to be incapable of powering a 100 amp alternator at load. The waterpump belt probably could but is seldom tensioned enough.

You're right. If kept charged it will work just fine. The first time the lights are left on or it takes extended cranking is when the trouble starts.

A 30 amp alternator puts out 3 times the current of the original generator and it does it at lower rpm. My short run time many starts tractor is charged by a generator with an alternator regulator. Would have to look it up to be sure but I think it has been 4 years now and never had a charger or booster connected. Not even after sitting all winter.

[Tyler Fontes]

On 4/25/2025 at 1:29 PM, Matt Kirsch said:

Looks like a Delco 10SI alternator to me.

Just because it's "100 Amps" does not mean it is generating 100 Amps of current constantly. It only creates enough current to maintain regulated voltage. That could be as little as zero Amps.

The only time the alternator would put out anywhere near 100 Amps is if there were a 100 Amp load on it. Even a flat dead battery doesn't put that much of a load on the alternator. My bet is it's not even capable of producing 100 Amps. Those claims tend to be inflated.

So will the 100amp alternator be okay to use on this tractor? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

[Tyler Fontes]

On 4/25/2025 at 2:41 PM, snoshoe said:

My experience says that a half discharged right after cranking is going to draw right around 60 amps. Pushing that much through a 12 or even a 10 gauge wire is just asking for smoke. That doesn't include the squealing belts. A single 1/2" belt seems to be incapable of powering a 100 amp alternator at load. The waterpump belt probably could but is seldom tensioned enough.

You're right. If kept charged it will work just fine. The first time the lights are left on or it takes extended cranking is when the trouble starts.

A 30 amp alternator puts out 3 times the current of the original generator and it does it at lower rpm. My short run time many starts tractor is charged by a generator with an alternator regulator. Would have to look it up to be sure but I think it has been 4 years now and never had a charger or booster connected. Not even after sitting all winter.

So will the 100amp alternator be okay to use on this tractor? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

[Tyler Fontes]

On 4/25/2025 at 10:39 AM, MacAR said:

I agree. A standard Delco 10SI alternator is just fine for this. Absolutely no need for anything bigger. 

Mac

So will the 100amp alternator be okay to use on this tractor? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

[Tyler Fontes]

On 4/24/2025 at 6:22 PM, MacAR said:

Personally, I'd tear all that out and start over. Here's the diagram I used on my H:

Pretty simple to figure out, but for a one wire setup you'd eliminate the two smaller wires from the alternator and the warning light from the system. I had to use the three wire setup because the H doesn't turn fast enough to self excite; your 300 might not either so just be aware of that if it doesn't charge. 

Mac

So will the 100amp alternator be okay to use on this tractor, even if I use the diagram as the setup? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

[Tyler Fontes]

Just now, Tyler Fontes said:

So will the 100amp alternator be okay to use on this tractor, even if I use the diagram as the setup? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

Can I also take away the voltage regulator that’s there? 

[snoshoe]

5 hours ago, Tyler Fontes said:

So will the 100amp alternator be okay to use on this tractor? Even if the tractor doesn’t even use nowhere near 100 amps? I also don’t want to burn anything up, like the starter and such! I just don’t want to go buy another alternator when this one works

Run an 8 gauge wire from alternator battery terminal to battery terminal of starter solenoid. Then if you want to know when it's charging. Install a voltmeter.