782, Kohler KT17 to Magnum 20 swap

[Shaner]

well i scrapped the idea of putting the command in my 782, only because the command i was about to get my hands on needed a total rebuild and im not up for that. so instead, i found a yard pro MTD lawn mower that surprisingly has a Kohler Magnum 20 in it that runs great for $200. now i know this question is asked a million times, but im wondering what is needed to do to the wiring to make the Magnum 20 work where the KT17 was? any input would be appreciated. ill try to put pictures up when i start the swap. shouldn't be all too hard.

[R Bedell]

You have two options.
(A) Install a relay to kill the engine when shutting down, or
(B) Install a new ignition switch from something like a 1810.

[Leadslingingdaddy]

Is the PTO going to be a direct fit on the MTD shaft?

[J-Mech]

You sure that yard pro has a horizontal shaft engine in it?........

[Shaner]

Yup its a horizontal shaft Kohler Magnum. Does anyone know the crank shafts are the same size on the PTO side of the KT and mag? The engine is sitting in the yard pro same as it would in a cub, with the flywheel side toward the back of the tractor

[J-Mech]

As per the parts book, a 782 (KT17) and an 1811 (M18) both have the same part number for the PTO. But, when Kohler builds a motor, sometimes there are specifications that change certain things as per the manufacturers request. I.E. The old "K" series engines in JD tractors has a longer crankshaft output than did the cubs. You might either get us the spec number off the motor, or just measure the shaft.

[Maple Cabin]

I did the swap, KT17 to M18 and added the relay to convert from source to shorted and it does not work very well. I blew the end of the muffler off. So if you convert got with a key switch for the mag engine. In stead of supply a voltage to the coil you need to release the short to the mag in order for it to fire a spark.

My relay works great to shut it down but will not allow enough voltage to pull the relay in to open the circuit to start. If you do it right the engine fires on the transition of the relay and that a total crap's table play (Not fun).

If you do the swap change the key switch to a magnetro engine and you're done

On the same swap I used an propane based engine and swapped carbs and have not a lot control of RPM. It's wants to really rev out.

Sorry off topic.

[R Bedell]

I did the swap, KT17 to M18 and added the relay to convert from source to shorted and it does not work very well. I blew the end of the muffler off. So if you convert got with a key switch for the mag engine. In stead of supply a voltage to the coil you need to release the short to the mag in order for it to fire a spark.

My relay works great to shut it down but will not allow enough voltage to pull the relay in to open the circuit to start. If you do it right the engine fires on the transition of the relay and that a total crap's table play (Not fun).

I have done the relay conversions on several of my family, friends, and neighbors and NEVER had an issue. Sounds like you are using the wrong relay.

[Shaner]

So if I'm reading this right....all I have to do is installed the key switch for the magnum engine in the cub and that's it? I thought there was more to it if I remember. RBedel do you happen to have a handy wiring diagram for the relay conversion?

[dale c.]

I just did a kt17 / m18 swap in a red ih 782 and I put a ignition switch in from the 1806 that the m-18 came from .the engine started and ran fine but when I turned the pto on it didn't work I checked it out and the terminal that grounds the ignition coil is the same terminal that is used to send power to the pto switch so I put the 782 switch back in and I unhooked the ignition kill wire out of the wiring plug at the engine hooked it to a push button that I mounted in the hole to the right of the ignition switch all you do is hold in the button to shut the engine off