Wiring 18hp Command in an 1872?

[smckittrick]

Is there a writeup somewhere describing what is needed to make this work?
THanks,
Scot

 

[sblunier]

Mag to Command should be like for like...both use magneto ignition (ground to kill).

Should have kill wire, charge wire, and oil sentry wire already...they should be like for like.

If the Command has a fuel solenoid, it needs to be hot in the run and start position of the key switch, as does an electric fuel pump.

 

[cmmorgan]

Steve,

So you are saying that you should be able to make a harness to go between the tractor and engine and everything should match up?

 

[smckittrick]

Thought someone said the mag was points.

 

[memorgan]

Scott
Some of the magnums did run a point ignition system
Think they were older
My son Caleb and i have swapped out several command
kohlors in mag tractors
I even shoved an 18 twin in a narrow frame on my plow tractor
Thats another thread all it’s own!
Its just a matter of getting a wire diagram and figure out how to make it work
Its not to tough
And we are here to help

 

[mgonitzke]

No Magnum ever had points. You are thinking of the KT-17.

 

[memorgan]

Well ,
I stand corrected,
Excuse me Matt

 

[sblunier]

Mick,

The Mag engines were all magneto ignition, but I can see how they would be confused with a KT....very similar in every way but ignition.

Do not ever wire a magneto to a std battery ignition key switch..... 12v to a mag kill wire (ground) cooks the magneto in short order.

 

[dropte]

Some Mag twin harnesses have a diode to the magneto kill wire built in to protect them from getting 12v on the wire to the magneto.

All Magnum twins are magneto engines, but they share a ton of components with the KT engines which are battery/points. Just have different flywheel, holes drilled in the crankcase for the points, mounting boss on cylinder barrel 1 for the magneto and wiring. Everything else is basically the same as a KT, though there is some parts variation in both the KT and the Mag engines over the run. They did build both motors at the same time, but the KT series was before the magnum series. I know they were building KTs into the 90s.

Converting from points to magneto isn't too tough. Going from magneto to magneto would be even easier. Should just be matching up wires. I like to pick up the original Packard 56 connectors (at least on the 82 series) and build the harness so it's plug and play instead of hacking up whatever is on the tractor. Just seems cleaner to me, and really isn't all that much harder to do.

 

[sblunier]

For clarification the OP is talking about work on a 1872. The 1872 would have only had a Mag 18 engine.

The KT's were only installed in the 82 series and the 1710/1711/1712 early CCC/MTD yellow Cubs.

 

[dropte]

From looking at the CH manual, I don't see anything that would be too tough to re-wire, but it depends on what sort of options the engine you're going to swap has. Looks like the CH18 has a 5 pin connector with pins for starter, accessory/oil sentry, magneto ground, 12vdc and Carb solenoid.

The M18 has a 3 pin connector that has 12vdc (from engine charging system), oil sentry and magneto ground.

If the CH18 has a carb solenoid, you'll need to either find a 12vdc switched wire, or wire in a relay (or disable the solenoid).

The starter relay for the M18 is separate from the engine and mounted under the 1872 pedestal. If the CH18 you're installing has the built in starter relay (I think most do), you'll need to remove/bypass the M18 relay and either wire it into the harness or run the wire down to the starter relay.

Other than that, Magneto kill -- Magneto kill, 12vdc -- 12vdc and oil sentry -- oil sentry should get you pretty close.