Green Plastic Chunks in Oil - M12

[svt721 27]

The bulk of the pics are in my last post at the bottom of the first page.

 

Edited May 12 by svt721

[WHX?? 51,312]

8 minutes ago, svt721 said:

 wise to pull them out for now.  Perhaps rebuild and reinstall in the future.

Pull them out and leave them out. Get use to perhaps a little more vibration or have a  while mowing you won't notice then. 

 

I don't know if I would pull the piston unless the bore looked iffy. @Achto says the piston comes out new rings gotta go in which doesn't hurt anyway i guess. 

Edited May 12 by WHX??

[svt721 27]

1 minute ago, WHX?? said:

Pull them out and leave them out. Get use to perhaps a little more vibration or have a  while mowing you won't notice then. 

 

I don't know if I would pull the piston unless the bore looked iffy. @Achto says the piston comes out new rings gotta go in. 

 

The bore appears to have a lot of vertical scratches but I'm not sure if that's just normal skirt wear.  I'll have to pull the head to see.  I assume new rings means a hone.  Or could the .003 rings be installed using a berry brush?

[WHX?? 51,312]

I'll let  @953 nut chime in on that. He's got a post to check the bore to see if boring or just honing will get it done. 

I was suggesting leave it in for now to get her back mowing quicker. A full rebuild if measurements dictate when you can lay it up over winter. 

[WHX?? 51,312]

If you pull the piston new rings for whatever oversize if any is in there now. New rings just a quick re cross hatch might be good.

Edited May 12 by WHX??

[953 nut 58,979]

7 hours ago, svt721 said:

  From what I can tell from the engine model #, these M12s don't have the balance gears.

That would be true for the 8 HP Magnum but not in the 10, 12, 14 and 16. look at page 12B-3 of this manual.

33 minutes ago, svt721 said:

has a small amount of wobble.

That is a sure sign the grenade- gears were about to cost you some serious money.

37 minutes ago, svt721 said:

 

Attached are pictures, let me know what you guys think.

I see plastic everywhere and that is only what shows on the surface. As was said by another person, the governor gear is plastic and if a chunk were to get wedged in tis teeth you would have a problem for sure. Time to do it right rather than wishing you had later.

 

[953 nut 58,979]

27 minutes ago, WHX?? said:

I'll let  @953 nut chime in on that. He's got a post to check the bore to see if boring or just honing will get it done. 

I was suggesting leave it in for now to get her back mowing quicker. A full rebuild if measurements dictate when you can lay it up over winter. 

This is a down and dirty way to check the bore.  If you can find the .003 over rings you will want to check the end gap on each ring at the top of the cylinder bore so you don't have then pinched too tight. The manual in the previous post has this information in it.

 

 

[oliver2-44 10,520]

3 hours ago, svt721 said:

 How has this never happened to anyone else?!?

Time to buy a Lotto Ticket!

[WHX?? 51,312]

3 hours ago, 953 nut said:

Time to do it right rather than wishing you had later.

Agreed Richard but the grass ain't gettin no shorter ... 

 

3 hours ago, 953 nut said:

sure sign the grenade- gears were about to cost

Absolutely ... don't toss em like a grenade tho... send them our way @Achto can make some dandy hitch pins with them. 

[953 nut 58,979]

8 hours ago, WHX?? said:

11 hours ago, 953 nut said:

Time to do it right rather than wishing you had later.

Agreed Richard but the grass ain't gettin no shorter .

Lets weigh the likely cost.      Rent a mower for a couple of weeks while saving the Magnum   VS   buy a new engine because the one that only needs to be cleaned up and re-ringed tossed the gears through the block.                    Better look up the phone number of that rental place.             

[squonk 43,202]

I think a drive over to VA to @richmondred01 may be in order. Get a new engine and get back to mowing. Tear down the existing engine and do it right.

[squonk 43,202]

A note honing. Unless you have a rigid adjustable hone, you're gonna be honing for days to remove .003" of material with a flex hone. 

[svt721 27]

Great information guys, I really appreciate it.  I pulled the balance gears last night - the OCD in me wants to replace bearings and put them back in, how much vibration am I going to see compared to running with the gears?

 

Richard - you're speaking the same words of wisdom that run through my head, do it right the first time.  I have a friend who can lend me a spare Deere 115 - never mowed with anything modern before haha.  Otherwise it may have been worth the drive to take you up on your offer.  Said friend knows a machinist that can take care of the machine work on the block.  That said, what do you recommend for a rebuild kit?  I see a few that have every internal component, but I don't know that it's necessary to replace valves or the rod (or the carb, coil, etc which is included in one kit).  My plan would be to take the block to the machinist and let him measure it, then order the parts.  I'm thinking I'd need piston, rings and gaskets.  Since there's so much plastic in the crank bearings I'm thinking it would make sense to replace those and the crank seals as well unless you think otherwise.  Is there anything related to the governor that I should replace?  Machine has a little over 1000 hours on it.

 

Squonk - I've heard of richmondred and would bring him the block for the machine work, but Richmond is a 10 hour drive round trip which I can't really justify right now if I can get it done locally.

[svt721 27]

14 hours ago, 953 nut said:

This is a down and dirty way to check the bore.  If you can find the .003 over rings you will want to check the end gap on each ring at the top of the cylinder bore so you don't have then pinched too tight. The manual in the previous post has this information in it.

 

 

 

Just read your post about measurements - I'll give this a try tonight and see what I come up with.  There is still light crosshatch visible in the bore, but it's definitely worn.  Will be interested to see by how much.

[WHX?? 51,312]

10 minutes ago, svt721 said:

the OCD in me wants to replace bearings and put them back in,

I can relate to that but let it pass ... your much better off without them. I have never done it but I heard tell it's a real pain to install them and get them timed right. Read the manual on doing it, it can be quite confusing for this simpleton anyway.

Some of the guys report no additional vibration or lack of smoothness ... some do. kinda like going to solid mounts on a shaker plate motor. 

 

25 minutes ago, svt721 said:

what do you recommend for a rebuild kit?

Some guys prefer the master rebuild kits which includes darn near everything. Personally I prefer to piece every thing out as some things like valves can be cleaned up and lapped. Much less costly that way and when you have 30 ... gulp... tractors to tend to. 

 

16 minutes ago, svt721 said:

related to the governor that I should replace?

No ... just make sure the flag is secured to the shaft yet. 

[svt721 27]

2 minutes ago, WHX?? said:

I can relate to that but let it pass ... your much better off without them. I have never done it but I heard tell it's a real pain to install them and get them timed right. Read the manual on doing it, it can be quite confusing for this simpleton anyway.

Some of the guys report no additional vibration or lack of smoothness ... some do. kinda like going to solid mounts on a shaker plate motor. 

 

Some guys prefer the master rebuild kits which includes darn near everything. Personally I prefer to piece every thing out as some things like valves can be cleaned up and lapped. Much less costly that way and when you have 30 ... gulp... tractors to tend to. 

 

Then out they will stay.

 

I need to pull the valves out anyway as there's plastic stuck in the adjusters so I'll see what they look like.  I went through and lapped all the valves when I went through the cylinder head on my old Saab a couple years ago and was pleased with the results so I'll give that a shot first.  I hate to replace things that aren't necessary but it's one of those "if you're already in there..." kind of things I guess.  Would you agree on replacing the crank bearings or just clean them out and let them roll?  

 

30 tractors, I think that counts as a heard!

[WHX?? 51,312]

5 minutes ago, svt721 said:

replacing the crank bearings or just clean them out and let them roll?

Inspect them I guess is all I can tell you. Most guy are are going to tell you to replace them. Richmond Red would but he is a pro builder and wants no call backs for his customers. His price reflects that but then again If that's what folks want. 

I think of all the rebuilds I have done I replaced them once. 

[svt721 27]

45 minutes ago, WHX?? said:

Inspect them I guess is all I can tell you. Most guy are are going to tell you to replace them. Richmond Red would but he is a pro builder and wants no call backs for his customers. His price reflects that but then again If that's what folks want. 

I think of all the rebuilds I have done I replaced them once. 

 

Ok, I'll inspect them once I press the crank out and make a determination.  Any recommendations on where to buy the piston/rings and associated stuff?  iSaveTractors and Lil Red Barn seem to have a vast selection but not sure on aftermarket parts quality.

[squonk 43,202]

On a worker that works hard , I would replace the bearings. If you're only using it to go get coffee,  leave them in. 

[953 nut 58,979]

5 hours ago, svt721 said:

 

Ok, I'll inspect them once I press the crank out and make a determination.  Any recommendations on where to buy the piston/rings and associated stuff?  iSaveTractors and Lil Red Barn seem to have a vast selection but not sure on aftermarket parts quality.

I Save Tractors has treated me right,  Never have done business with Lil Red Barn but have heard they are good people too.

6 hours ago, svt721 said:

 I hate to replace things that aren't necessary but it's one of those "if you're already in there..." kind of things I guess.  Would you agree on replacing the crank bearings or just clean them out and let them roll?  

Replace them!

[WHX?? 51,312]

I  like Red Barn ... Just finished up a K with their stuff and all was good. I'm sure it's off shore but for just running to the mail box or to get Squonky a cupojoe. 

 

 There's another seller on fleabay that has off shore ...  bat for kids ... or somethin like that that I have used alot for engine guts and never had issues either. Guys are saying I save has ok stuff too but guessing that's off shore as well.

 

Some guys ... the ones without 30 tractors  like to stick with Kohler rings and if I was building a hardcore worker I would consider it. 

 

14 hours ago, squonk said:

a flex hone. 

Those are called dingle berry hones Squonky ... get it right! 

[squonk 43,202]

The last 3 K181's I have done, I have used parts from I Save Tractors. The gaskets are high quality. 

[Fordiesel69 270]

I usually do not take the magnum grenade gears out till 2500+ hours.  Their construction seems to be more durable than the K series.

  

[kpinnc 14,140]

On 5/13/2025 at 9:11 AM, svt721 said:

I pulled the balance gears last night - the OCD in me wants to replace bearings and put them back in, how much vibration am I going to see compared to running with the gears?

 

In a 12hp engine that is direct mounted (no isolation cradle mount), the vibration will be minimal just due to the shorter throw of the crankshaft. On a 14 or 16 it is more evident, but still not terrible. It is also usually more noticeable at lower RPM. 

 

 

[oliver2-44 10,520]

On 5/13/2025 at 8:11 AM, svt721 said:

I pulled the balance gears last night - the OCD in me wants to replace bearings and put them back in, how much vibration am I going to see compared to running with the gears

The shafts also wear. If I recall correctly they have 0.0005 the wear tolerance. So many are worn just like the bearings.