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osenga

allis 712 replaceing motor

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osenga
On my 712 over the summer the balance gear went out the side of my motor. SO needless to say that motor is done for . but last weekend i picked up a 12hp kohler 25.00 could not say no for parts but it was out of a old cub it is a 1969. I was wondering if there is any one that has mounted one in a simplicity and how you might shim it up so the drive shaft would line up and be straight. And if so do you have a digram to drill the holes to mount the motor?

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osenga
they are different sizes the pan that was in it was like 10 in width and by like 6 and the cub motor is 6 x 6 and pan is only half inch tall unlike the simplicity pan is 3 inchs tall

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Chris727
Unfortunately most cub engines do not swap into Simplicitys. Kohler has made so many different blocks that its ridiculous. Most of the cub and deere engines don't have the ears on the block needed to bolt the pan on.

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osenga
ya I went out to the shop and looked at it today ya the block is smaller . yes yes this block dont have the ears on it etiher. but it does have a flat pan not one of them that has a drop in it . So what i am thinking if i drilled the 4 holes bolt through the bottom of the 712 and straight into the motor bolt holes

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sbull78
ah yes..i remember when my dad and i had found a motor for his cub 149 we could make a simplicity motor work for it but not the other way around if i recall...

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Chris727
Since this comes up pretty often here is a rundown of major differences in K-Series single cylinder blocks: Here is the base of a typical multi-purpose Kohler K341S. This was from a Massey but has the same base as the Simplicity engines. Below are the ears needed to attach the 2qt oil pan.




The above engines were used in many stationary and agricultural applications as well. Not all blocks with ears are interchangeable. There is another variation of "eared" block, I have seen these on some Massey Fergusons, and the example below is from my John Deere 214. On this tractor, the flanges at the base of the block are not used for mounting the oil pan, they secure the engine to the frame. Note: John Deere 214 tractors used 2 different types of blocks, I think this is the earlier one.


This engine is flat all across the base and does not have the recesses for adding an oil fill tube. This is one of the "rarer" ones from what I've seen. The pan threads on from underneath and this engine has the long dipper. Pan is seen below.


The third block is the most common JD and Cub block, this is an NOS K241AS shortblock for a 1974 JD 110.


It has a flat pan, and a short dipper, I suspect this is similar to Osenga's engine. You can't put the 2qt pan onto it as there are no mounting ears and the pan is much wider. Even if it was possible, the short dipper on the rod likely wouldn't pick up the oil in the deeper pan.


In my experience, there are more of the engines around that do fit the Simplicity tractors than those that don't. They were used on lots of generic applications, I see them at farm sales, craigslist, etc. I wouldn't be surprised if you could sell the cub engine for enough to buy the correct engine for your Simplicity, you might even get a cub guy to trade you. Most of the time an engine with an "A" in the model # is not interchangeable, for example the K241AS, whearas the K241S can be made to work fairly simply.

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BLACKOUT
You mentioned that your $25 cub engine had a flat pan: I would double check that is is not a 10hp. Check above the crank output shaft for a K241 or K301 in the casting. 12 hp cubs usually have the deep cub pan.

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HubbardRA
I mounted a 12 Hp Cub engine on my 61 Wards (Simplicity 700) back quite a few years ago. I used threaded rod that I screwed into the mounting holes. Then I put locknuts on the rod up against the bottom of the oil pan to keep the rods perfectly rigid so they couldn't work loose. I then measured to the lowest part of the pan and cut spacecers from 1/2 pipe that were just long enough for the lowest part of the pan to clear the flat bottom of the chassis. I drilled out one end of the spacer just enough to fit over the locknut so the spacer would sit solidly against the oil pan. With the homemade studs in place I sat the engine on the tractor and lined up the engine the way I wanted it to set and marked around the ends of the studs. This was done without the spacers in place. I drilled the holes, then installed the spacers and bolted the engine down. I used locknuts that assembled from underneath the chassis. You do also need to cut a hole so the plug can be removed from the oilpan to drain the oil before you bolt the engine into the chassis. I used a holesaw for this, but you could use a torch or a grinder, or even drill a series of small holes then knock the metal out of the hole with a hammer, depending what you have to work with. To attach the driveshaft I just used a flat plate. I drilled holes for the four 1/4 bolts that went into the Cadet flywheel, then drilled two holes for the Simplicity driveshaft to mount to. I measured the length bolts that would be needed to bolt up the driveshaft and installed those bolts before bolting the plate to the flywheel. Then I installed the spacers that were needed, then the flexplate and bolted up the driveshaft. You don't have to get the driveshaft absolutely straight. All you need to do is make sure the centerline of the engine crankshaft stays parallel to the centerline of the chassis. In other words, "Do Not" try to angle the engine and make the crank point directly at the BGB shaft. The two shafts need to stay parallel in both directions, but can be offset as much as an inch and will still run smoothly with the flexplates. Just make sure that when you bolt up the driveshaft that you are not putting tension on the flexplates when you tighten the mounting bolts. I usually loosen the set screws in the driveshaft collar on the BGB shaft and let it float till the flywheel end of the driveshaft is bolted solid, then re-tighten the set screws. The conversion was really fairly easy. PM me if you decide to try it and need any advice.

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