Troy-Bilt push mower -- flywheel problem?

[tunahead72 2,424]

I could use some advice here…

 

I have an older Troy-Bilt push mower with a Briggs & Stratton engine that we bought new in 2005.  It's served us well over the years, until some IDIOT recently found a way to run over an iron pipe hidden in the weeds.  The mower stopped immediately, with a loud clanging noise, and a couple of four-letter words were screamed into the neighborhood.  I checked the blade for damage, and didn't notice anything unusual at first, but when I started it there was noticeably more vibration than before, to the point that it hurt my hands to try to hold onto the handle for more than a minute or so.

 

A couple of days later, I started checking the vibration issue more closely.  The blade was definitely bent, so I tossed it and replaced it with another much newer and straighter blade.  I started the mower, it felt better, not perfect, but I was able to mow with it for about an hour or so with no problems.  The engine seems to be running a little rough, with some vibration felt in the handlebars.

 

I checked the bottom of the crankshaft, where the blade attaches, and observed that the crankshaft is a little bent.  I used a framing square to estimate how much it's bent, and it seems to be only ≈ ⅛" or so, which doesn't seem like a lot to me, not perfect, but might be acceptable.

 

I've tried several times to remove the blade adapter to check it more closely, using a 2-jaw gear puller that my father-in-law gave me many years ago.  It doesn't look bad to me, but so far I haven't able to remove it to know for sure.

 

Finally, I checked the flywheel key for damage.  The key was sheared, but not broken, which could explain the engine roughness.  The slots in the crankshaft and the flywheel were only a few degrees off.

 

I successfully removed the flywheel using a flat pry bar under the flywheel, replacing the flywheel nut flush with the top of the crankshaft, and gently hitting the nut with a 3-lb. drilling hammer.  It only took a few taps to pop the flywheel loose.

 

Here's what concerns me…  The flywheel has several very small lines that MAY be the beginning of cracks, but may just be casting marks, I don't know.  They're nowhere near as bad as others I've seen on YouTube, but they're visible, and I wonder if you guys can help me decide whether I should be concerned.

 

Here's a bunch of photos….

 

Before removing the flywheel:

 

 

Top of flywheel – nothing unusual here?

 

 

Underside of flywheel – this is where I see the lines I mentioned, are these cracks or just casting marks?

 

 

Crankshaft (top), looks OK to me:

 

 

And finally, the sheared (but not broken) key, which I'll replace with a new genuine Briggs & Stratton key:

 

 

Questions or comments, put 'em below, I'd appreciate anything you guys can offer!

 

[JoeM 7,874]

No concerns using the flywheel. If it is going to fail, it will fail when you tighten it down. Do not lubricate the shaft or the flywheel just clean. and don't use an impact just hand wrench and best a torque wrench to spec.

The bent output shaft can be straightened and there are several vids on the tube show how.

[Achto 27,624]

Flywheel looks fine to me, I'd run it. The 1/8" bend in the PTO shaft may not seem like much, until you're running at 3600RPMs. Then there will most likely be some vibration.

 

 

[tunahead72 2,424]

Thanks gentlemen, that's a relief about the flywheel.  I do plan to use a torque wrench on it...  I've seen specs from OutdoorPowerInfo.com and other sources that say 55 ft.-lbs. for the flywheel nut for this series of Briggs engines (it's a 125K02), does that sound about right?

 

Taryl's video was one of several that I saw for straightening the crankshaft.  It's a good one, but I'm a little nervous about hitting the shaft with a hammer.  If I can get the blade adapter off, I might be more inclined to use a pipe like Steve's Small Engine Saloon does in this video (although his method is risky too):

 

 

[gwest_ca-(File Mod) 11,062]

On 8/31/2023 at 2:12 AM, tunahead72 said:

I could use some advice here…

 

I have an older Troy-Bilt push mower with a Briggs & Stratton engine that we bought new in 2005.  It's served us well over the years, until some IDIOT recently found a way to run over an iron pipe hidden in the weeds.  The mower stopped immediately, with a loud clanging noise, and a couple of four-letter words were screamed into the neighborhood.  I checked the blade for damage, and didn't notice anything unusual at first, but when I started it there was noticeably more vibration than before, to the point that it hurt my hands to try to hold onto the handle for more than a minute or so.

 

A couple of days later, I started checking the vibration issue more closely.  The blade was definitely bent, so I tossed it and replaced it with another much newer and straighter blade.  I started the mower, it felt better, not perfect, but I was able to mow with it for about an hour or so with no problems.  The engine seems to be running a little rough, with some vibration felt in the handlebars.

 

I checked the bottom of the crankshaft, where the blade attaches, and observed that the crankshaft is a little bent.  I used a framing square to estimate how much it's bent, and it seems to be only ≈ ⅛" or so, which doesn't seem like a lot to me, not perfect, but might be acceptable.

 

I've tried several times to remove the blade adapter to check it more closely, using a 2-jaw gear puller that my father-in-law gave me many years ago.  It doesn't look bad to me, but so far I haven't able to remove it to know for sure.

 

Finally, I checked the flywheel key for damage.  The key was sheared, but not broken, which could explain the engine roughness.  The slots in the crankshaft and the flywheel were only a few degrees off.

 

I successfully removed the flywheel using a flat pry bar under the flywheel, replacing the flywheel nut flush with the top of the crankshaft, and gently hitting the nut with a 3-lb. drilling hammer.  It only took a few taps to pop the flywheel loose.

 

Here's what concerns me…  The flywheel has several very small lines that MAY be the beginning of cracks, but may just be casting marks, I don't know.  They're nowhere near as bad as others I've seen on YouTube, but they're visible, and I wonder if you guys can help me decide whether I should be concerned.

 

Here's a bunch of photos….

 

Before removing the flywheel:

 

 

Top of flywheel – nothing unusual here?

 

 

Underside of flywheel – this is where I see the lines I mentioned, are these cracks or just casting marks?

 

 

Crankshaft (top), looks OK to me:

 

 

And finally, the sheared (but not broken) key, which I'll replace with a new genuine Briggs & Stratton key:

 

 

Questions or comments, put 'em below, I'd appreciate anything you guys can offer!

 

I recall some keys are offset like that but don't know which ones. I would go the ipl for this engine and get the correct key just in case.

[tunahead72 2,424]

2 hours ago, gwest_ca said:

I recall some keys are offset like that but don't know which ones. I would go the ipl for this engine and get the correct key just in case.

 

Interesting...  I've never had one of these apart this far, so I wouldn't know about the offset.  I do have a parts manual for this engine model saved onto my laptop, which shows part #222698S, which supercedes to several other numbers, including the 5002 that I bought directly from the official Briggs online shopping site.  Here's what it looks like:

 

 

Just a quick update...  Yesterday I cleaned the crankshaft and made it nice and shiny with some emery cloth (no lube), installed the new flywheel key, reassembled everything (torqued the flywheel nut to 55 ft.-lbs.) and tested.  There's very little difference in the way the engine runs, and I still feel some vibration in the handle.  So it seems that the key wasn't the main source of the vibration, and the next step is probably unbending the bottom end of the crankshaft, preferably with a pipe, or with a hammer if I can't get the blade adapter off.

 

I'm shopping for a stronger 2-jaw puller as we speak, and seeing everything from a 3-piece set for $30 from Harbor Freight to pullers well over $100 that are certainly overkill for this job.  Anybody have any recommendations for a reasonably priced decent quality 2-jaw (or combination 2/3 jaw) puller?

 

Edited September 1, 2023 by tunahead72

[Gasaholic 224]

Only offset keys pretty much were on some Tecumseh engines - Briggs pretty mush only ever used the one 222698 flywheel key in L-Heads, with a few exceptions on older Letter series, etc which had a bolt-on key, and a few that had half moon keys but 99.999% of the Briggs flywheel keys I had ever replaced, stocked, or had problems with were the aluminum 222698 keys. (the 5002 part number was briggs display packaged version of same key)  Aftermarket keys also work fine.  Flywheel pullers , there were a few different sizes, and relatively cheap - the ones that you use self-threading bolts into the puller holes were the better ones than any jaw pullers.