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Discussion Starter · #1 ·
I have a 317 with the hated Series one Kohler. Recently I came across a Kohler Magnum 18 removed from a Cub Cadet. I had no idea of the condition but only paid $50 bucks for it so what could I lose? After rigging it up on the bench and discovering a severe knock was nothing more than a loose flywheel which was taken care of with a turn of a wrench, I have been thinking about replacing the series one with this engine. Everything I can find points to a bolt in conversion. Except the PTO clutch. The series one has a smaller shaft but appears to have a bushing.

My question is, does anybody out there know it the standard clutch supplied with the series one has a bushing that can be removed and if so, what is the bore of the clutch without the bushing installed. The engine came with a good operating clutch but the pulley is about an inch smaller and a larger belt. The mower would be too slow using this pulley. I am reluctant to bore the series one clutch as I would like to keep the series one as a spare. Once it's bored out, I would be committed.

Also, the Magnum doesn't have a high speed adjustment on the carburetor. Will the series one carb work decently on the Magnum? The Magnum runs pretty good on the bench but does have a stumble on acceleration and I have no way to put a load on the engine. That seems to be the only question so far.

I have owned this tractor for many years and have not had one problem with the series one engine (other than points) but I would estimate the engine has something near 3000 hours on it. I mow two acres a week in the hot Florida weather, 3 to 4 hours per mow and have been doing so for five years. I bought it used and was told it had 2 thousand plus hours then. It owes me nothing! It leaks but otherwise runs strong. The rest of the tractor is in very good condition.

The Magnum being a newer version of the same engine seems to be a good conversion. And cheap. Solid state ignition (mags), remote oil filter, fully lubricated crankshaft and one more horsepower which I don't need or care about.

So what am I missing?

Thanks for any help that comes along.
 

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My guess would be --- the diameter of the shaft. the 317 is 1 inch. Cubs I've read are 1 1/8 inch.

The PTO clutch will not fit if that is true. But you can get an adapter and use a 318 PTO.


Might find someone putting a Predator in their 318 your 317 PTO will fit the Predator. And the 318 PTO is large enough that it can be bushed down to 1 1/8.
 

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Discussion Starter · #3 ·
Thanks for the info. That might be a solution although folks seem to want an arm and a leg for these things. (clutches) But if that was all I needed to do, that would be acceptable. Any idea what the shaft size is on the 318 PTO?

Thanks again...
 

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Discussion Starter · #5 ·
Doing a little more research and scanning photo's of various clutches on Ebay, I noticed so far that all of these clutches have 6206 bearings front and back which have a inner bore of 30 mm. (1.181 in) Which means they all have adaptor bushings in the driven disk. This is also true of the clutch assembly which came with the Magnum engine. (Cub) So, I should be able to use the Magnum bushing on my clutch solving 1/2 the problem. I would have to bore out the disk on the crankshaft. So, I'm looking for a reasonably priced 317 series one (bad) clutch so I can leave my present as is.

I'm not necessarily cheap, but as I said above I have no idea how the Magnum will run under load and I may be reinstalling the original. Hope not, but I don't want to do something silly.
 

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A Magnum is a great replacement for a KT17 engine. Along with the PTO crankshaft diameter issue you have probably seen postings here as to the required ignition circuit changes and the mods for an oil filter on the Magnum. Your thoughts on swapping the clutch adapter bushing are reasonable. However, compare the thread pattern on the Deere KT17 and Magnum closure plates, as the Deere and Cub engines I have seen used clutches and closure plates with differing patterns for the four clutch-mounting bolts.

A KT17 carb will work on the Magnum (with some linkage changes), although the more sophisticated Walbro carb used on the Mag-18 must be responsible for the extra horse.
 

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Mitchel,
Yes, indeed there is more to the story. The horsepower rating will depend on which carb is used and whether the engine is set to operate at 3200 or 3600 rpm max.


Joe,
Is there a spec number on your Magnum engine and can you see a number in the carb throat?
 
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Discussion Starter · #9 ·
Thanks everyone for the help. It's amazing what these blogs can provide these days.

As for the engine information. it seems the one thing Koehler wasn't much good at is data plates or tags. The tag on this engine has been torn half off. What I can read is what I believe to be the spec number of 2450?? the last digits are gone. The other visible number is 18316. It is a M18S for sure. That much can easily be seen. As for the carb? Only the Walbro name with no other numbers visible. Perhaps they are on the underside. Again, I have no immediate need to change the carb, I was just thinking that if the engine had a faulty carb, perhaps I could swap it out with the KT17 if necessary. The grass keeps growing down here and I wouldn't want to get into a long wait for parts if I can avoid it.

I have the wiring figured out. Having worked on aircraft most of my life I'm quite familiar with Magneto's. This engine ignition is in no way "electronic". Just good old mags. Nice and simple! I already purchase the appropriate key switch and that should keep all other circuits in good condition. I thought about the relay that many talk about but for the lack of a $20 key switch didn't seem like a good reason not to do it that way. I even have several appropriate relays laying around from my aircraft days but still decided not to use them. Just something else to cause problems on what is a very simple circuit. My intent is not to disparage anybody here by saying that. I sure I don't offend anybody.

Having bench run the engine with everything working well including the charging circuits, fuel pump, and starter, no smoke, I think I'm ready to take the plunge. I just need to resolve the PTO issue.

Over the years I have owned several 300 series JD's however I bought this 317 being ignorant of the series One engine issues. The fellow I bought it from mentioned it and priced the machine accordingly. That was about 7 years ago and "Johnny" as my grand-daughter calls it has served me very well. No series one issues at all other than points and condensers. I even mow on banks having over 200 feet of ditch to mow and a raised mound septic system. It is easily ten times the tractor of what you see in the big box stores. They make me cringe walking by them. I can't understand why Deere would do that to there name.

I am concerned about the heat issue. Again having years of aircraft experience with air cooled piston engines, heat is their worse enemy. Hence my thinking of installing an oil cooler next to the oil filter the Magnum came with. Any advice here would be appreciated. It's remotely mounted and should be relatively easy to install a cooler and fan if necessary. Most of the summers down here the ambient temps are in the high 90's a humidity about the same number. I have measure head temps well over 500 degrees which is not good. With aircraft engines which are very similar although much more horsepower, 400 degrees is considered critical. That is my only concern with the machine. Other than that it is perfect for what I use it for. It seems all of the water cooled JD's are quite a bit larger and much more expensive. I consider my self very lucky to come across this engine so reasonably priced and so well regarded. Less than a hundred bucks and some time seems like a good deal to me.

That's my intentions. Hopefully I don't waste too much of everyone's time but I sure appreciate any advice you may have. Thanks again.
 

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Discussion Starter · #10 ·
I have notice the differences in the clutches. The Cub is much lighter and smaller. I guess that says something about the John Deere quality built into the machines. I would only be using the hub adaptors and none of the Cub's other clutch parts. I just want to avoid doing anything that can't be undone if this turns out to be a fiasco.

Thanks for the help.
 

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I bought my 317 as a non running tractor. I put new rods and rings in the series I and it runs fine. Apparently those series engines were not friendly to hillsides. But all I have is flat land. I figured that engine last for over 30 years, surely it'll last a while with some refreshing. Just my opinion.

Sent from my SM-N920V using Tapatalk
 

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Discussion Starter · #12 ·
Doug,

I certainly agree. The series one has done a great job for me too. And obviously the previous owner. I have approx. five hundred feet of hillside I need to mow every week. Maybe those with issues lived on a cliff? Sometimes things just get a bad wrap. I had a Ford diesel that the entire world seemed to hate. I sold it with over 360k on it! And it still ran perfectly in every way. I can't even say I am a fanatic with maintenance. I just don't abuse things but I do believe in taking care of equipment to a reasonable degree.

My only motive for this conversion is pure curiosity. Life without points and condensers would be nice but the series one will not go far away. I do need the machine to run dependably as the only option is over a hundred bucks a month to contract mowing and one of my favorite pass times is cutting the grass. I don't think I'm doing anything other than updating and I intend to keep this machine as long as possible.

What the heck is "Tapatalk"?
 

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It's an app for android phones(and Apple I suppose.) When you don't have access to a computer, you can use tapatalk to communicate through this site and others. Back to the swap. My hesitation was the fact of cutting the frame to be able to accommodate the oil filter housing. I too had a good Kohler Magnum 18 that I was seriously considering putting in my 317. But for me, rebuilding the series I seemed to be easiest way to go. That is without any modification to the tractor itself. Would I like to put lets say a 23 hp Kohler down in there? Heck yeah! Talk about a horse! Or should I say big buck. And I agree on cutting grass. At one time I had several mowing accounts, plus my day job. Good luck with what you choose to do. Go Green!
 

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Joe,
Just to comment on the Magnum engine numbers you provided earlier... The 2450 likely corresponds to a Mag-18 spec 24506 used in Cub tractors per the Kohler data base. Likewise, if the 18316 represents the first digits of the serial number, this would indicate a 1988 engine. So, there is little doubt that you have a Mag-18 with a Walbro fixed-jet carb with a main jet sized for 3600 rpm and 18 hp (some later Mags had an "emission" carb with a smaller main jet and rpm limitations with lower horsepower).

With regard to you concerns about engine over-heating, it would be worthwhile to pull the tin off the Magnum engine in order to clean the cooling fins and engine block prior to installation. I too have had good experiences with KT17 series I engines. Yours has provided exceptional service comparable to other highly-regarded air cooled engines.
 

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Discussion Starter · #15 ·
Thanks for that info. Cleaning the fins is a good idea that I should have thought of. I would most like have done it at the install as my shrouds and baffling are in much better condition and I intend to transfer most of them with both engines on the bench. As for the HP, I have always been happy with the 17 horsepower the KT17 put out. Due to the heat issue, I seldom ran it at full throttle. And the grass never suffered from that.

Above, it was brought up that the oil filter on the Magnum interferes with the tractor frame. Or vice versa. This engine already has the remote oil filter installed. Do you have any knowledge as to if I will need to whack a hole in the frame using the remote filter? I wouldn't care for that too much but it wouldn't stop the project. Just need to plan ahead if it is necessary. I still haven't determined exactly where the filter will be mounted. It will likely require new hoses as these are only 8 - 10 inches long. In the end I want the tractor to look the same as it does now if at all possible. You really see some hack jobs out there.

Again, thanks for the info.
 

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Here's a picture of a 317 with the oil filter direct on the engine. The corner of the frame was cut at an angle, and the motor mount needs a piece welded in at an angle so that part of the horizontal and vertical portions can be trimmed. I would guess that it should take less or no trimming to make the remote adapter fit, but I don't know. I haven't actually seen one. The remote filter will certainly make it easier to add a cooler.
 

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Discussion Starter · #17 ·
That seems reasonable. But would that hole interfere with the cooling? As the shrouds are still on the 317 I can't really see exactly how much room is in there. Looking at your photo it appears to have plenty of room judging from the size of the filter. (I have a photo of the remote setup but for whatever reason I can't upload it.) But the adaptor plate and lines could easily fit into the space this filter occupies without any cutting. Thanks again. The photo helps a lot.
 
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