Tecumseh 16hp Flywheel magnets

fpappal

Member
My cousin picked up an old Tuff-bilt tractor which has an original Tecumseh 0H160 engine on it. I believe it was made in 1977. He drove it around the yard one time and turned it off. It would never start again!!! The engine all of a sudden lost its spark. I told him I would try to fix it for him so here is what I am dealing with. I took the flywheel off this afternoon and found all the magnets which were originally attached to the inside of the flywheel had broken loose. I have never seen this type of set up when I removed the flywheeel, all these little "modules" of wrapped wire. I am assuming it is for some sort of charging system on this engine? My question is, can I just glue the magnets onto the flywheel? It is so rusted I cannot see where they were originally. Do I just space them evenly or do they need to go in specific locations? I have rebuilt quite a few engines but I have never seen one like this, or had one with magnets that broke loose. any suggestions?
In the picture the magnets are magnetically attached to the "modules".
a177690.jpg
 
Hope you haven't removed those magnets yet. They are in the correct position in the picture. You could mark them as you remove them.

There is a guy on youtube "taryl fixes all" that has a video on putting the magnets back on a flywheel. One thing he shows is how to figure out the orientation of the magnets.
I've put in a single magnet in a kohler flywheel and it never gave any problems. Where they go in the flywheel has to be pretty clean though. If you glue to rust, the rust will push them back off pretty soon.

Note: those magnets are not why your engine won't run, unless your problem is a dead battery. That thing with all the little wires wound around it is the stator, and it creates the electricity to charge the battery when the magnets move past it.

I am thinking your ignition source is the item (module/lamination/whatever) above the flywheel, bolted to the 'fins'. It probably has its' own magnet on the outside of the flywheel.

Some of those Tecumseh ignition parts are no longer available. But there may be some way to work around that problem. If it has external points in a box on the side of the block, you may be able to use an automobile ignition coil and condenser. There probably are other fixes out there on the internet too.
 
If the flywheel backplate,alt stator,ign module & block reflect the condition of inside of flywheel I wouldn't even consider trying to reinstall magnets on flywheel,as they will probably break loose in a short time in addition you still have determine position of magnets & direction of each.Ask your cousin if he's prepared to throw some serious money at this eng/tractor.

What you are looking at in pic is the alt stator as trk said,in addition to charge coils on same there is also a SEPERATE coil mounted on stator frame that generates power for the ign module,with no magnets on flywheel you get no electricity to module & no spark,also the open frame design of alt stator indicates same is a 20A stator,the standard stator used on many HH/OH eng is 10A and the stator has fewer coil's & is covered in thin aluminum banding.The 20A stator would dictate a different magnet size/design from the standard 10A flywheel setup,if you don't have correct flywheel to match the alt stator alt & ign module may not work.

Checking my microfiche cards(parts list) for the OH160 eng there are 6 different pn listed for flywheel depending on SPEC# of eng,what the actual difference between them is I don't know,what you need to do is get spec# off eng & click on link below and lookup eng mod/spec# in the Tecumseh eng listings,then goto ebay & search Tecumseh flywheel and see if you can locate a used flywheel same pn as the one listed for your eng,also while there search for a Tecumseh service/repair manual on a cd that covers your mod# eng.
tecumseh
 
I hope you haven't cleaned up anything yet.
Having the magnets stuck to the stator is an enormous help in determining the correct placement of the magnets.
If you have removed the magnets there is still hope.
Take one magnet and try to match its placement to the flywheel. Look for any signs ie. rust, dirt, grime or glue markings.
Remember the flywheel is a mirror orientation to the stator. Then one by one return the remaining magnets to their proper placement on the flywheel.
The magnetism will hold the magnets in place.
When you have all the magnets returned to the flywheel and are satisfied with the location and orientation then take a Sharpie marker and make tick marks on the flywheel rim to indicate the locations of the magnets. Mark each magnet with some identifying scheme that makes sense to you. A-L/R, B-L/R, C-L/R, etc.
When all this is done and you are satisfied with the placement clean everything. Use steel wool to clean the flywheel and the magnets. Remove all the glue.
Reattach the magnets with JB Weld. Don't use the JB Quik. Mash the magnets down with finger pressure. The magnetism will hold the magnets in place.
I have repaired two such engines with loose magnets. The second I remembered what I learned from the mistakes made in the first. The magnets are very brittle and will break.
I broke one on the first engine. I then had seven magnets instead of six. I still got it to work but you could tell on the ammeter something wasn't right.
Instead of a steady pointer the needle vibrated, but it did keep the battery charged and worked the lights.
The magneto coil is that thing above the flywheel. It has its own magnets mounted on the outside of the flywheel.
 
Thanks for all the comments. It amazes me how much knowledge is out there, you just have to ask.
So of course I removed the magnets, never even gave it a second thought about the proper orientation. There are not marks at all on the inside of the flywheel, just rust. I am not even positive how many magnets I should have. I have 4 complete magnets, and 1 magnet that is partially broken. There are many smaller pieces however which leads me to believe there was 6 originally. Would it make sense that the magnets took up the entire circumference of the inside of the flywheel? What is the best way to clean up these magnets? All the small metal filings are obviously sticking to them.
I may just try and glue what I have to the flywheel and see how they work, assuming I can get the flywheel and magnets clean enough.

Is there definitely a specific direction they need to go in? End to end the magnets attract each other, if I turn one 180 degrees it still attracts to the other. It is only when you try to stack them on top of each other that they repel. So it seems like end to end does not matter. Or is there more to it?

I may also put a wanted ad on craigslist and see if someone has one laying around.

Thanks for all the help, I will keep you posted.
 
I'm not familiar with this engine. All the Briggs engines I've worked with have a gap between the magnets.
 
You are correct Pete. Acually any lawnmower engine is that way. They are an even number usually and are glued on NS SN NS SN All of the way around. In reality a Stator is actually a very crude altinator with either a diode or a voltage regulator turning it to DC. That is why the test procedures tell you to see if around 28 volts AC is on the two outer wires. Cut that in half to 14 volts and you have your DC charging voltage. Somtimes you wish a car, truck, or tractor was that simple.!
 
Here is the video from Taryl The vid shows a B&S engine I believe, but the same basic theory applys to all small engines I believe.

https://www.youtube.com/watch?v=DUGK_H-Sulc
 
I put an ad on craigslist and within a half hour I had a guy tell me he has one. Turns out it is the exact flywheel and he wants $50. He also has th stator if I need it. Planning on picking it up tomorrow. Hopefully it doesn't fall through. I figure I might as well buy the stator too, not really sure if the one I have is damaged or not. Thanks for all the help. I will let you know if I get it to fire.
 
In the last year I have tried to learn all I can about small engines. From what I understand, the stator, and magnets you are referring to have nothing to do with the "firing" of the motor. It is the magnets on the outside of the flywheel that make the "fire". Is this correct?
 
(quoted from post at 16:45:23 11/12/17) In the last year I have tried to learn all I can about small engines. From what I understand, the stator, and magnets you are referring to have nothing to do with the "firing" of the motor. It is the magnets on the outside of the flywheel that make the "fire". Is this correct?
Hi you had better get a Tecumseh manual and do a little more studying that is not correct for a OH160 and many other Tecumseh engines
GB in MN
 
(quoted from post at 19:04:28 11/12/17) Yep, the magnet on the outside is for spark. Magnets on the
inside charge the battery.
NOT on a Tecumseh OH160 there are no magnets on the outside of the Tecumseh flywheel better get a manual also
GB in MN
 

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