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Removing Tecumseh rotary flywheel

Posted by sfhellwig 6a SE Kansas (My Page) on
Wed, Jun 16, 10 at 16:18

This is addressing part two of my mower repair. I diagnosed and replaced the coil, only to find that the kill switch is now not disengaging. Of course it's under the flywheel and I can't clean it properly so the wheel needs to come off. In another thread I have already been warned against using a pulley puller and I understand why. The flywheel is pretty thin and would likely be damaged.

Several people have described the process of prying upward while striking the crank. While it works I am afraid mine may be pretty seized due to the age of the motor. I also don't want to damage the crank. I don't have a brass hammer or a knock off tool. I have seen described how to make a puller but wonder about threading the bolts. After pulling off the starter cup I found three holes that I assume would fit the puller. However the holes are smooth and untapped. The person that built their own puller said they used 1/4" self tapping bolts. Does this sound like a viable method? Any additions? It is simple fabrication and doesn't have to be heavy duty. Probably only be used once. Will the self tapping bolts damage the flywheel or is that what would be on the puller sold for this? I will likely pick up a few extra nuts to fashion a knock off tool also. I know if won't be the same but it would likely be better than striking the crank. I would rather do the puller anyway as I just don't feel comfortable hitting on any of the machine with too much force.


Follow-Up Postings:

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RE: Removing Tecumseh rotary flywheel

Dude you getting away ahead of yourself , see my last reply to your original post , never try self tapping fasteners within the flywheel of your Eager 1 . Carefully read that the flywheel is supported when you gently strike the crank shaft end. There is axial end play on the crankshaft assembly (thousands of an inch). Either with the Flat Pry Bar or Hard Wood Taper Shims you are protecting the internal bearings when you lightly tap the crankshaft end . We cannot reverse engineer a solution to your problem any clearer . Since your motor is quite old ...again you should utilize penetrating oil sparingly on the shaft while gently tapping the shaft end to initiate capillary action (creep) of the oil to assist within removal of the Flywheel the next day. Be patient , Not Rocket Science . If your mower was here I would have had it removed in less time than it has taken to respond to your concerns lol .


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Wed, Jun 16, 10 at 20:20

And be sure to have the bail wired to the handle to disengage the brake,with the plug wire OFF.

I've never had a flywheel that didn't come off. When I put the heavy blade screwdriver or tire iron under the flywheel and lever it against the engine, I pry up with enough force that the wheels of the mower almost lift off the ground.


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RE: Removing Tecumseh rotary flywheel

I have heard that a harmonic balancer puller can be used to pull a Tecumseh flywheel. You can get one from Harbor Freight right now on sale for $9.99. If a HF store is close by, you can ask for the web price and they will honor it.

Here is a link that might be useful: Harbor Freight puller set


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Thu, Jun 17, 10 at 6:00

You can use the balancer puller for many flywheels, but really, it takes 10 seconds to remove the Tecumseh flywheel without it.


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RE: Removing Tecumseh rotary flywheel

Well I don't think I was getting ahead of myself because guess what, I didn't come off. This is really one of those things I wish I could be learning in person as that person would know how hard they could strike or not. I supported the flywheel (can see the endplay) and tried tapping and rotating. I used combinations of several smaller taps and a few more abrupt. I let penetrating oil sit for several hours. I reread all instructions and even maintained patience. Then the patience ran out and I knew damage would ensue. I know I'm missing something small, but I'm frustrated. After this is all done I will go back to my "parts" mower and try that to see if it is just this one that is particularly stuck. I may even go and try the Craftsman one last time to see if the penetrating oil did more with more time.

The only reason I get to stop is because I decided to try removing the switch from below again and did manage to get it out. If the brake were not worn as far as it was I could not have done that. Now it's a matter of the "terminal" is always grounded and I can't figure out how it became like this or how to bend the wire so it disconnects properly. But I think I will likely just replace it also. So close yet so far.

That balancer puller was shown in a list of accepted ways to do this. And cheap enough to win over fabbing one up quickly. But it comes back to one of my original issues, what do you do about the un-threaded holes in the flywheel. If someone would humor me in addressing that, do they have to be tapped with a traditional tap or were they just never meant to be used? I will probably never own or make the puller but unanswered questions tend to stick with me.

Once this switch is fixed/replaced it will all be over and I will not likely have to work on a mower again for a while. You guys have been great, very helpful and supportive. I know more about my mower (and these engines in general) than I expected to learn in this period of time. Thanks.


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Thu, Jun 17, 10 at 11:23

You probably aren't hitting the shaft with enough force. I don't have a flywheel in front of me to see, but I would tap the 3 holes first. If I were doing it without success, I heat with a propane torch, a circle about 2 inches away from center of the flywheel to expand the aluminum and then apply a cold water soaked rag to the crank center only to shrink it. Then use the hammer and lever.

How hot to heat? Enough to burn my finger if I touched it.
I don't want you to do that, because you don't have experience and a fire could ensue. So, don't do it.

Anybody who does this should be outside, away from any building, with a fire extinguisher at hand, with the fire department on scene and the fire truck in the driveway.


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Thu, Jun 17, 10 at 17:39

I had a clunker that I was going to junk and since it was a Tecumseh engine, I made a you tube video of how to remove the flywheel.

It took two good raps to break it free.

http://www.youtube.com/watch?v=gmOp08vppGI


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RE: Removing Tecumseh rotary flywheel

Wow cannot believe that the flywheel is being that stubborn ! As Baymee has advised , heating the flywheel and quenching the shaft may in itself free the galled flywheel , Heed his caution and ensure all residual grease Oil Gas has been removed. Properly Tapping the head is risky at best . Your Head is most likely designed for a four finger cup puller . The fingers cup under the Flywheel , again as tight
as your's apparently is I would hesitate on this use since it will most likely crack the Aluminium and you still require the stiking of the Centre Bolt of the Puller. Check out Bay's Video and you will see the proper technique and force req'd . Otherwise a Professional will be req'd . Hope You or the Penetrating Oil Win out ...T .


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RE: Removing Tecumseh rotary flywheel

I appreciate the video very much. I know it was a short clip and didn't look too difficult but you still took your time and I thank you. It shows me two important things. 1) The knock off tool is far more substantial than internet pictures make it look. Just threading the stock nut on or stacking multiple nuts is not going to equal that. 2) That is more force than I was thinking or using. Which brings me to the final conclusion that without the knock off and a brass hammer there is no way in Hades I am trying that anymore.

I am moving along though. As mentioned above I got the brake/switch out from under the flywheel, which is the whole reason for this in the first place. I can't figure out why the switch won't disengage but I have one on it's way.

I had forgot about the heating. I have seen it on TV so many times when engine builders are installing a timing set on a V8 (reverse principle). I'd love to try it some time. When this mower finally goes for good I am totally taking it apart and practicing what Baymee shows. I really want to accomplish it but can't risk the damage. Thanks again for all the help.


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RE: Removing Tecumseh rotary flywheel

NOTE: If you are going to use the BFH trick to hammer the flywheel off, first screw the flywheel nut back onto the crankshaft, up-side down, flat even with the top of the crankshaft. This will keep you from boogering up the threads, and will leave enough space to allow the flywheel to break loose! Sometimes yer aim is not so good, ya know?!
A large brass hammer is best to use. I stick a large screw-driver in under the flywheel, being careful not to damage anything there, then lift the mower up with the screw-driver almost vertical, then SMACK it several times with the hammer, and they always come loose. You must allow the mower to hang from the screw-driver, at about 55-60 degrees. Note: Baby whacks don't count!


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Fri, Jun 18, 10 at 11:22

Here is a picture of that very same crankshaft. Notice that it is pretty rugged.


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RE: Removing Tecumseh rotary flywheel

I had a clunker that I was going to junk and since it was a Tecumseh engine, I made a youtube video of how to remove the flywheel. It took two good raps to break it free.

Mr. Baymee,

Does the direction you're prying with the screwdriver in relation to the position of the flywheel matter?
ie does it matter if the screwdriver is in line with or perpendicular to the flywheel key?


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RE: Removing Tecumseh rotary flywheel

  • Posted by baymee LehighValleyPA (My Page) on
    Fri, Jul 23, 10 at 20:44

I would keep the driver perpendicular. You have to be careful because there is a rubber domes breather under there. You should be able to look underneath for a good solid metal surface for the point of the screwdriver, or use a tire iron.


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