# Engine Simplicity 12HP to 13 HP Greyhound )



## harpmaker (Feb 20, 2011)

Engine Swap Simplicity 2012 Landlord to 13 HP Greyhound (Harbor Freight)

Having rebuilt the original engine several times We felt it was time to find another Horizontal shaft engine replacement. This is an OLD tractor 40 years old. The shaft diameter is irrelevant

unless you need it for a front mounted snowblower or something. We’re going to remove the pull starter and use that end just like Simplicity did with the Briggs & Stratton. The rotation is the same as B&S. I read a suggestion somewhere to use the shaft end. That will give you three speeds in reverse and one forward. Not a good idea.

First remove the hood and the negative battery terminal. Remove the side plates. Remove the front assy(grill etc.) Pay careful attention to the connection of the drive shaft from the engine. Don’t lose anything. I suggest you take a picture or draw it out for future reference. You’ll need it and then some. Remove the old B&S engine. This is a heavy rascal so having an extra pair of hands or a chain hoist is a good idea. Next remove the generator/starter. And all the wiring Except the wire for the lights. Now remove the fan from the old B&S. Set this aside for now but don’t lose it.

Unpack the Greyhound 13 hp engine. Being sleeved aluminum it’s much lighter. Don’t panic if it seems to have no compression. It has a centrifugal compression release. Remove the pull start assy - you won’t be using this. Also remove the fan shroud. Put the bolts back in the holes so you don’t misplace them.

Now remove the coil pickup (again replacing the bolts.) This is necessary so the flywheel gears don’t catch on it. Now mark the position of the fan screen, the fan, and the flywheel. (Mark all three). Remove the flywheel nut. 

Using a puller - remove the flywheel. I had to take a large heavy washer and drill three holes in it - then using three 1/12" to 2" bolts my three legged puller popped it loose. (Don’t lose the key from the keyway.) If you’ve got enough sense to tackle this project you know enough not to pound on the end of the shaft or pry on the cast flywheel so I’ll refrain from telling you not to do so. At this point carefully tape the two magnets inside the flywheel and the one on the outside.

Trust me you’ll be glad you did after you drill and tap the holes in the flywheel.

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You may have another idea about my next several steps. I will tell you it worked. I will not tell you it was without several problems and possible pitfalls. (ie I needed a machine shop) Here’s what I did. 

DSCM0988.jpg DSCN0989.jpg DSCN0990.jpg

I cut the fan blades from the old B&S fan - keeping the hub. Next I used the threaded holes to carefully mark the flywheel for two holes. (The threaded holes are closer together therefore placing the holes in the thicker part of the flywheel nearest to center-look at the underside.) I sharpened the ends of two 3/8" bolts and put wet paint on them to make my marks The placement of these holes is the most critical thing you’ll do in this entire project. Do it wrong and you’ll end up botching it badly. I drilled 5/16" holes in the flywheel (It won’t hurt if you go through) which I tapped with 3/8" 16 NC threads. Now you can remove the tape from the magnets. I then enlarged the threaded holes in the old hub to11/32 to give myself some room for error. Enlarge the holes in the old pulley/spacer and enlarge the little round spacers too. If you epoxy the round spacers in place it makes assembly much easier. You’ll have to drill holes in the plastic fan to match and in the fan screen.

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Now I cut the can like top from the center section of the fan screen. I used a hack saw, then ground down the rough edges. Next I heated the can below the screen and reformed it to clear the two holes now in the flywheel. I don’t know what kind of steel was used for this piece but it took me several hours of heating and pounding before I was able to get it done. It wasn’t pretty but it worked. DSCN0994.jpg

OK a trial fit shows that the fan and the metal cup/hub and the screen will mount to the flywheel.

With clearance for the two bolts. DSCN0995.jpg

Re-install the flywheel. Using three thicknesses of typing paper as a spacer on both ends replace the pick up-coil and tighten the two bolts. Remove the spacer. Tighten the flywheel nut.

At this point you should have the fan and reshaped hub installed. Replace the fan shroud.

DSCN0998.jpg 

At this point I ground the sharp edges from the old fan hub with a belt sander. Don’t use a grinding wheel as the aluminum will build up on the wheel. If you don’t have a belt sander use a coarse file which you’ll need to clean afterward with a file card. 

DSCN0999.jpg

Mount the old fan hub and the small pulley with it’s round spacers temporarily on the engine with 5 ½" 3/8" bolts.

If you have a piece of metal sticking up on the front of the tractor’s engine plate It’s gonna’ be in the way. Take a pipe wrench and bend it down toward the front to allow clearance for the engine to be placed. If you haven’t degreased the area where the engine is to be placed, do so now.

I had some old rubber rollers from my mower deck and I cut rubber mounts1/2" thick to go under the engine. They were necessary to cover bolt heads for suspension mount. Otherwise the engine wouldn’t set level. 3/4" thick in the front resulted in better alignment with the drive shaft. DSCN0998.jpg 

Temporarily place the engine in it’s new home and align it carefully with the drive shaft for proper length. Now you see why we retained the old fan hub for an additional spacer.

With the engine centered I used a Q-tip and white paint to mark where the engine mounting holes were needed. I drilled ½ " holes. It’s slow going you’ll need a good drill bit and patience.

A bit of oil helps too. The engine will be mounted with fairly long 3" or 3 ½" 3/8" bolts. I also found I had to trim the rubber spacers to clear the bolt holes.

Now you can connect the drive shaft loosely and bolt down the engine. Some bolts will have to be inserted from the bottom up so be sure to use lock washers. You will be compressing the rubber pads so try to tighten all engine bolts evenly. Good luck with that. Then tighten the drive shaft bolts & nuts. You’ll need to replace the positive battery cable with a 36" (91.44 cm) 4 gauge top post terminal. The old cable is interrupted by the starter button. Replace the red wire furnished with the engine. Connect the black wire to a convenient hole in the firewall and the original negative battery cable to the same bolt. Connect the negative battery terminal to the battery. DSCN1001.jpg

PUT OIL IN THE ENGINE. Add some gasoline and be prepared for the engine to start quickly.

Make sure the tractor is out of gear. I was able to get out of the way when mine started.

I later connected the throttle cable to the engine using the original lever. There are two holes and a cable clamp already on the engine. I did have to loosen the throttle pivot bolt as operation was stiff. For now I’ll leave the fuel shut-off and the choke where they are. And leave the ignition switch where it is as well. For the time being I’ll use the supplied gas tank as the tubing is smaller than that used on the old tank. From this point on it’s all cosmetic so you’re on your own. DSCN1000.jpg
PS -You'll have to raise the rear hood-latch screw holes and re-thread them


Good luck with your conversion. You’ve given new life to a real garden tractor that will plow snow and even plow your garden. It has steel gears not plastic ones. They don’t build ‘em that way any more. 

I have 17 step by step pictures if you decide to do this project I'll zip them and send them to you.


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## wjjones (May 28, 2010)

This is great DIY info for other members Thankyou for sharing it with the forum.


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## Hoodoo Valley (Nov 14, 2006)

Looking good! Does the extra HP really make a difference?


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## harpmaker (Feb 20, 2011)

*Engine Simplicity 12HP to 13 HP Greyhound )*

We don't really know yet. We have two other lawn mowers one is Simplicity too. It has a B&S twin 18HP. Although the one with the engine change has a mower deck, as a mower it'll be backup. We plan to use it primarily as a pull/tow tractor or with a blade if we ever get enough snow in E Tennessee. We've got some downed trees we plan to pull out of the woods. We have weights and chains for traction. We'll keep you posted on how it does.

harpmaker


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## wjjones (May 28, 2010)

harpmaker said:


> We don't really know yet. We have two other lawn mowers one is Simplicity too. It has a B&S twin 18HP. Although the one with the engine change has a mower deck, as a mower it'll be backup. We plan to use it primarily as a pull/tow tractor or with a blade if we ever get enough snow in E Tennessee. We've got some downed trees we plan to pull out of the woods. We have weights and chains for traction. We'll keep you posted on how it does.
> 
> harpmaker


 Where is Etowah, Tennessee??


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## dangeroustoys56 (Jul 26, 2010)

Thats similar to what i did with my 69 broadmoor- i have the original motor ( all in pieces) - since i wanted to have an updated motor ( didnt want to invest in alot of parts if the originals didnt work), i swapped a '80's 10HP briggs in place of the original 8HP briggs - still being a flathead but just a bit larger, it was a tight fit.


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## wcwsimp67 (Jun 3, 2013)

*Can you pls send me the step by step pics?*

Harpmaker,

Would you kindly email the step by step pics to me ? I'll privately message you my email. 

Thanks


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## harpmaker (Feb 20, 2011)

Finally - the site now likes my password. This is still a great conversion. Pretty straightforward. My e-mail is [email protected] no problem to post as it's a business E-mail anyway.


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