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7thofa2nd 08-23-2018 04:33 PM

1 Attachment(s)
I have a 4hp Tecumseh engine that I'm prepping for a mini bike project. The guy I bought it from (a shady sorta guy) said the boy ran it through a mud puddle and it stopped running (much of what he had told me turned out false). So, I've been disassembling the engine to see what the problem could be. Thankfully, nothing got sucked into the internal parts. I cleaned the carb and it actually wasn't all too bad. But now, I pulled off the flywheel (the first time I ever removed a Tecumseh flywheel) and found 2 magnets that I'm guessing belong there, but they were simply stuck to the flywheel because they're magnets. It looks like they were bonded to the flywheel at some point, but no longer are. I can put them back to where they were because of the glue-ish material left behind marks where they were. Can someone tell me a little about these magnets and what I could use to bond them back in position?

THANKS in advance for any help.

mckutzy 08-23-2018 05:19 PM

This a thread that should be in the engines or All other parts section....

As for the magnets... they are for a charging circuit, that typically comes with an electric start engine as this has a ring gear.
It is kinda hard to tell, but is the magnet 2 separate pieces or does it appear to be broken in half?...
If 2 separate pieces, then youll need to find out where the pieces need to sit when glued back...
Epoxy will be used... a good 24hr 2 part mix will be fine..

-The pieces need to be cleaned of all epoxy bits and the FW aswell. The magnet seat of the FW will need to cleaned with sanding it rough to expose the steel and allow a good bonding surface.

-Clean all pieces/FW with a brakekleen or the like to eliminate finger oils and other greases..

-If there is a gap between the magnets like in the pic above, you will need to cut some wood sticks to fit that gap as a spacer for when you are ready to glue the magnets..

-Mix epoxy well, also have a few wooden sticks to use to back against when clamping.

-Apply sparingly to the parts and the seat, clean up excess.... clamp carefully as not to allow the magnets to get crushed or pinched off angle...

-Allow to set in a room temp environment for at least 24hr to fully cure...

-After cure, carefully remove the clamps/wood blocks and check to see if the magnets have firmly glued themselves to the FW...

When reassembling, check to see if you have enough air gap between the magnets and coil, aswell as no other collisions

itsid 08-23-2018 07:02 PM

and since mac's right..
•MOVED• ;)

One thing though..
looks like they DO NOT belong there IMHO..
I doubt tecumseh was careless enough to simply glue magnets inside the flywheel (two on one side)
without balancing the wheel ..
so either the magnets should go on opposite sides of the flywheel (so their weight cancels out [more or less])
or you are missing a counterweight on the other side.

IF you want the magnets (say you have AND need the charging system)
carefully place the magnets so the flywheel still is as balanced as possible,
if you don't only reglue the magnets if the flywheel is out of balance without them (which I doubt)


mckutzy 08-23-2018 07:44 PM

Ahh yes balance is quite necessary on a flywheel... You'll have to consult a specialist on that... I just have the experience for DC/permanent magnet motor mechanics.

7thofa2nd 08-23-2018 09:28 PM

My first question is... how do I know for sure that I do actually have the magnets in the right position? Second question... what happens if I don't? (more questions...) What if I'm off a little? Is there some markings I should be looking for on the flywheel? If I clean the surface, I won't have anything left to show me where they were.

It does have an electric starter... but it's 110v.

---------- Post added at 10:20 PM ---------- Previous post was at 09:36 PM ----------

@itsid ...Nope, don't have a charging system. So I don't need 'em?

---------- Post added at 10:25 PM ---------- Previous post was at 10:20 PM ----------

Is a Montgomery Wards mini bike even collectible enough for me to worry about what engine I put on it? I have several others I can use... I'd like to just get the thing put back together and running. Those magnets are the only thing holding up finishing it.

---------- Post added at 10:28 PM ---------- Previous post was at 10:25 PM ----------

Well, I don't know how my latest comment got attached to my other comment above but...

I'll get they hang of this yet.

itsid 08-24-2018 02:04 AM

no charging system no internal magnets necessary.

position doesn't matter for the charging system the charging coil doesn't care about the stroke,
just IF a magnet passes by.

w/o a charging coil, you only need one magnet on a flywheel (usually on the outside) for the ignition coil.. it's position is important (since it triggers the spark).

If you want it original or not is something I cannot answer for you..
I doubt there's much difference in value if you swap the engine, on the other hand there's a fanbase for nearl everything, so it doesn't harm to make it right ;)

You posts got merged since we do not like double posting around here
and we have an auto-merger that mostly takes care of those.
you have an edit button in your posts lower right corner,
use that to add infos or change your post in case noone answered yet.


ezcome-ezgo 08-24-2018 08:18 AM

I don't think there is a burgeoning market for Teckasheema flywheels.

7thofa2nd 08-24-2018 08:59 PM

Well, I followed instructions and JB-welded them on... so I guess we'll see tomorrow whether it was successful or not, and go from there.

mckutzy 08-24-2018 11:35 PM

Jb might blow up on you... I know it's a different type of epoxy... It might hold it when stationary , but does it have the strength like when it is under a centrifugal force.
I'd be wary for sure..

itsid 08-25-2018 04:35 AM

hopefully the balance was tested before jb welding the magnets back on, otherwise it'll be one **** of a testrun.
You didn't say so... but you have been warned... so what now?

I'd trust in JB weld for that too..
there isn't much of a force that tries to break the magnets loose anyways..
and the biggest involved force is centripetal and forces the magnets onto the rim of the flywheel, the epoxy just has to deal with the inertial forces of the magnets
(keep them in place as the flywheel accelerates)
and it shouldn't degrade as the engine heats up.

Maybe it's optimistic but I'd say JB weld can do both *shrugs*
(on properly prepared surfaces that is)


Randy H 08-25-2018 09:12 AM

2 Attachment(s)
Looks like an old points Tecumseh. The magneto assembly is tucked away under the flywheel. If that is indeed what you have here's a you tube video on setting the points and timing. Likely it doesn't have a charging system at all.

7thofa2nd 08-25-2018 12:22 PM

@itsid... nope, didn't check the balance (don't really know how to do it) and am just trusting (hoping/praying) it's not needed. Living dangerous!!!

I watched a few youtube videos on the topic, and everyone swears by JBweld. And, I tend to agree with you... "there isn't much of a force that tries to break the magnets loose anyways..." I think it would take an obstruction, something hitting the magnets to knock them loose. I did just set the flywheel on and turned it by hand to see if everything cleared OK. :thumbsup:

---------- Post added at 01:17 PM ---------- Previous post was at 01:12 PM ----------

@Randy H... THANKS. That looks like my setup. I did reset the points, but I'm leaving the timing as is, for now at least. And, I don't see anything that indicates it has a charging system.

---------- Post added at 01:22 PM ---------- Previous post was at 01:17 PM ----------

@mckutzy looks like the guys on the youtube videos recommend JB weld overwhelmingly. It's all a learning experience for me... and what better teacher is there than an explosion anyway? Ha!!!

I'm just taking it slow on each step and following instructions... we'll see...

mckutzy 08-25-2018 02:36 PM

JB is a DIY technique.. A 24hr epoxy is a professional choice... You may spend a bit on it but it'll hold...

7thofa2nd 08-25-2018 02:59 PM

DIY technique... I'm in the right place then. :thumbsup:

7thofa2nd 09-03-2018 08:03 PM

I'm ready to flip out!!!
OK, my mini bike project should have been finished 2 weeks ago. I THOUGHT I wanted to stay with the engine that came with it. What a **** mistake!!!

Let me know where I did stupid stuff as you read through this.

I pulled the carb off, the shroud off, the gas tank, exhaust, head, and flywheel off. I bonded the magnets back on the flywheel with JB weld. I order a new head gasket using the numbers off the shroud... I get the head gasket and it's too small. I'm figuring it's a 5hp shroud on a 3 or 3.5 hp engine, who knows. ****, for all I know now, it could be a **** 2hp. But, that was the only number I could find. I'm ****ed, but oh well.

I cleaned the carb which wasn't all that dirty, but it was missing the main mixture screw at the bottom of the bowl. So I just figured, WTH, I'll just buy a new carb and be done with it. I find a number on the carb... 580 8h28 and proceed to check out ebay and Amazon for a new one. I type in the number and it takes me to every Tecumseh carb but what I need, and none of them reference my number. I go to some tech site to see if I can cross reference my number with... ?
I get a list of 50,000,000 Tecumseh carb numbers for various carb parts... I assume, but my number isn't there. WTH becomes WTF!!!

I did see a few carbs that looked like mine, but the descriptions said they were for larger engines.

Jump in here at any point.

My brain hurts from spending a couple hours on my search. I NEED HELP... PALEEEZE!!!

BTW... the engine is looking really pretty.

:surrender: :censored: :surrender: :censored: :surrender:

Nosandwich 09-04-2018 04:40 AM

This is a good example of why it's a good idea (and we prefer) that you keep everything pertaining to one kart in one thread.

All the other information we need is in the other thread.

itsid 09-04-2018 05:49 AM


Originally Posted by Nosandwich (Post 507782)
This is a good example of why it's a good idea (and we prefer) that you keep everything pertaining to one kart in one thread.

All the other information we need is in the other thread.

100% correct!
And that's why the threads are now •MERGED•

Also: please pick the correct forum for your threads, that one AGAIN was in the wrong one!

Now, if you want to know what engine you have. measure bore and stroke...
displacement is a good indicator of engine size!
Also: posting pics helps a ton..
especially if you're unsure about model/types.


7thofa2nd 09-04-2018 08:04 AM

Mea culpa...

Not exactly sure how to measure bore and stroke... then how to proceed with that information.

ezcome-ezgo 09-04-2018 08:36 AM

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7thofa2nd 09-04-2018 12:24 PM


Originally Posted by ezcome-ezgo (Post 507794)

Thanks ezcome-ezgo for the clarification... that's pretty much what I was thinking, but my thinking has been a little sketchy lately.
OK, I have 2 3/4" bore, 1 15/16" stroke = 11.0 cu. in. so it's an ECV110 reference code I.

I've located the right head gasket. The carburetors are another story... the ones I'm looking at so far look much different, but I'm still looking.

Oh, and the reference chart doesn't list the h.p. for my engine.

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