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Gary

Wiring Harness Question

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Gary

I'm still working on my 917H Allis, and have decided to make a new wire harness. I have a brand new M18 Kohler, to install. My thought is to set up the harness for the M18 from the get go. I'm not an electrical guru. I am guessing that I would need an ignition switch for a Briggs (anybody got a part number). As for the wiring itself, I'd also guess that I should use a wiring diagram for a 7116, with the Briggs engine. Am I going in the right direction?

Any and all help is greatly appreciated.

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Brettw
quote:Switches are switches. Brand won't matter.id="quote">
id="quote">

I could be wrong, but I believe the Simplicity ignition switches for a Briggs engine is different from the switch for KT17 engine. A switch is a switch, but what and how it switches can be very different. One is ground to kill, the other turns off power to the coil to kill.

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SmilinSam
quote:Originally posted by Mike_H

Switches are switchesid="red">. Brand won't matter. I would pattern the original harness, and make modifications as necessary.


id="quote">
id="quote">Good philosophy to cook your tractors wiring harness and set fire to the tractor.(seen that done several times with people using just any old switch)Basically you have 2 types of switches. Battery ignition switches and magneto ignition switches. In each of those types there are a number of ways the different tractor manufacturers arrange the connection terminal spades. So you cant just throw any old switch in and plug N play...Wiring a KT powered tractor to a Magnum powered tractor is not a complicated matter. The only part that really changes is you drop the wire from the keyswitch powering the battery ignition and add a wire from the keyswitch to kill the engine, changing from a battery ignition switch to a magneto ignition switch.On switches, sometimes the spades are marked for what they do and sometimes they are not.Battery ignition switches usually have B-Battery, R-rectifier regulator, S-start, I-ignition, A-accessory(or something like that)Magneto ignition switches usually have tabs marked M-mag, B-battery, A-accessory(or L-load), S-start, and G-ground(which goes mostly unused)You can take a test meter and see for yourself which tabs are "Live" with which key positions.On the BI-battery ignition switch b,r,i, a are all live in the run setting. S and I are on in the start setting. all are dead in the off setting.With the MI-magneto ignition switches, the S is live in the start setting, the M is live(to ground and G tab too) in the off setting, the A and B are live in the run setting. This is off the top of my head, so I hope its all right info. Like I said best to do/ learn for yourself with practice and using a meter to see what the keyswitch tabs do in each key position.So..when you go from KT powered tractor to Magnum powered you will tie the wires to the R tab on the BI switch into the B wires on the MI switch. Then you will turn the I wire on the BI switch into the M wire on the MI switch. That wire will now go from the m tab on the MI switch to the kill wire on the Magnum engine. All that wire is going to do now is ground the kill wire on the engine when the key is off.The B wires are same from B tabs switch to switch and so are the A/ L tabs from switch to switch, as are also the S tabs from switch to switch.Clear as mud ..right?sm00

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Mike_H

Ok, I stand corrected...If just replacing a switch, yes, you would want the correct one.

OP was talking about building a new wire harness, and not just replacing a switch. When building a new harness, you would match wires up to the correct terminals on the switch, and pin the connector appropriately. A little forethought, and a heavy dose of "measure twice, cut once" philosophy goes into electrical work. Its not as complicated as some people make it, but you do have to be cognizant of how the current is flowing, and making sure your common doesn't intersect your power (dead short-->BAD)

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Gary

Thanks for all the information. I think I'm going to use a switch that is correct for a magneto ignition, and wire the harness accordingly. Don't think I'll ever go back to the KT17 anyway. May rebuild it someday.

If anyone thinks of anything else for this project, feel free to chime in.

Thanks again!

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