IH 682 Repower to M18
 

My son and I purchased a really nice m18 to put into his IH 682. We are in the middle of the tear down and cleaning phase and I want to see if anyone has done a KT17 to M18 conversion. Below are the items we foresee needing help with but will take any suggestions. Thank you in advance.

- Wiring - the current tractor has a 2 wire plug going to the engine and the M18 takes a 3 plug. Any advice on what needs to be?

- PTO - I have not measured how far the pulleys sit away from the engine but I know they are different sizes. Will there be any issues using the newer, larger pulley PTO from the M18?

The M-18 is a drop in replacement for the KT-17 except for a minor wiring change. There are two ways to handle that. (A) Install a "kill relay", or (B) install a different Ignition Switch.

As far as the PTO:
IF the M'18 came out of a cub cadet, it should have the same PTO pulley.
If it didn't, but the crankshaft is the same diameter, your KT17 PTO will bolt on.
Post some pix of it, if this is not the case.
Do take care removing the PTO assy as you do not want to damage the pulley or mounting flange.
You will also have to remove the lower muffler attaching nuts to get to the studs on the
upper PTO mount.
At times the old muffler does not want to come off the exhaust nipples because it is rusty, also the clamps are rusty.(don't beat on the old rusty muffler)
do note most times it is easier to remove the exhaust manifolds with the muffler, but taking caution not to break the exhaust manifold studs off while loosening the nuts.
(It sounds more complicated than it is)
Wiring:
You will find a white magneto kill wire coming out of the grommet with the 2 spark plug wires on the fan shroud, that wire, when grounded, will kill/stop the engine.
Since you do not have a ign coil, you will not need/use the coil power wire from the ign switch.
later on we will tell you, as Roland mentioned, how to wire up a relay to kill the engine or replace the ignition switch with one that has a stop/ground/kill position for stopping the magneto from producing spark.
Clear as mud? :bigthink:

My bad, my comment was based on a M-18 coming out of a Cub Cadet product. M-18's coming from "others" may have more modifications.

:bigthink:

Model and Type of the engine should tell that.

I replaced a KT17 Series II with a Command 18 (link in signature).

The topic is about the M-18, though.

Thanks for the feedback.

As far as pulley size, the original KT17 has. 4.5” pulley and the M18 has a 6” pulley. The m18 came out of a cyclops that I purchased for the dual hydro controls. It just so happens it had a great running, low hour engine.

I believe I am going to try the relay approach to the wiring. I found the attach wiring diagram online and thought I could reuse the relay from the donor tractor (pic attached). Let me know if anyone disagrees with the diagram.

My father makes replacement motor to plate bushings since the original are thin and can eat into the engine case. Just thought I would share what has worked for us.

The larger spacers will work well, although I've not run across a situation where the factory spacers had a problem, but
I can understand if the bolts came loose there might be a problem.
I can't comment on your schematic, as when I blow it up to see, it is as fuzzy as a kitten.
There is a relay diagram on this site that Roland can link as I lost my saved links when my hard drive done quit.:BangPC:

Let me know if this version is better.

It's still blurry but from what I can see, it will work.
The operation theory is:
Basically the relay terminals you are using for mag ground are normally closed, that grounds the white wire, until you power the relay.

Powering the relay with the wire that normally was for power for the ignition coil,
opens the relay contacts so the magneto is no longer grounded.
That coil wire is powered in run with lights (if equipped), run, and start positions of the ignition switch.
Ya I know, you didn't need all that info, but it might help someone who wants to know how simple stuff works, and my coffee is still brewing. :biggrin2:

The three wires on a M18 are a oil pressure switch wire that would go to the dash lamp "sentry", one from the voltage rectifier, and one that is the kill wire to the magneto.

Your kill relay circut is good, I'm running the same setup except using a toggle switch for 12v on pin 85 and my kill wire connected to 87a, (six or one half dozen to the other) it has worked flawlessly.

In regards to the pulley though, with a larger pulley on the engine you'll overspeed the charge pump which will create more heat and damage, maybe even cook it. A small change from 4.5 - 5" is probably not a cause for concern but a +1.5" will be.

Unless there's something I'm not aware of with this particular setup but as far as I've always known, it's not a good idea to speed up a hydraulic pump/motor faster than it was designed for. I am new to the world of Cub Cadets though so someone please set me strait if I'm out of line here! Lol

I have an update on the wiring, the engine starts, charges and shuts off without the need of grounding the white wire? I currently don’t have the white wire from the m18 hooked to anything.

As far as the pulley, I do not understand the feedback. Since it is a PTO pulley I was assuming it would only impact the speed of the mower deck/snow blower when turned on?

My mistake, I was assuming there was a charge pump running off the pto.

No worries, I appreciate the feedback.

Just a thought, could the engine be shutting off with the key and no white wire attached due to the fuel solenoid? I am confused why it’s working properly without the white wire. I rather be right than lucky.

I have a late M-18's with a walbro carb, and it does have a shut off sol. but your engine would not run unless you have a power wire to that sol.
I was told by the previous owner of that motor was out of a cub.
What i don't know, is what cub it is out of, and what the carb is off of.
He said it was out of a 782 but that don't mean it was born with it. :bigthink:
I will say it runs sweet with that bad reputation walbro carb. :beerchug:

I see two wires going to the carb. One seems to be a ground and the other is super thin. I assumed it was some type of solenoid. Picture attached but is turned 90 degrees counter clockwise for some reason.

Dat sho' looks like a walley bugger car du later wif a fuel shut off solenoid.
Dat wood 'splain the stoppin without a kill wire. :biggrin2: :beerchug:
I would still use a either a relay or an ign switch to stop the engine instead of a fuel sol.

I had that problem on another forum, even rotating the photo before uploading didn't work but I figured out a work around on my own and it's always worked...crop the photo before uploading, even just a tiny sliver has always done the trick for me!

I hope that helps!

It may be redundant but I think you’re right on still hooking up the relay.

Thanks for the tip on images.