K341 Rebuild

[John G 9]

Hello all, I thought I'd sign up and share my experience and document my progress, since I've been getting so much info here for rebuilding this K341. Maybe people can get something out of it and if anyone has any advice I'd love to hear it as I go. The engine is off my dad's 416-8, and it ran really good until it suffered what my dad thought was a governor gear failure--it went into over-rev meltdown mode all of a sudden. Until I get the crank and cam out I won't know for sure but the governor gear is still in place, so I'm not sure if that was the cause or not.  I'm waiting on a valve spring compressor to arrive and the drive pulley is refusing to come off so it's soaking in kroil penetrating oil. Surprisingly the flywheel came off pretty easy after a 24 hour soak and using a cheap harmonic balancer puller.  The tractor has 1800 hours on the clock, and the clock had stopped working some time before my dad got it so it could have twice that much time on the engine for all I know.  It amazes me how good it looks inside, and how little wear there appears to be. I guess I'll see when I measure everything, but everyone who had this tractor must have done well with regular oil changes.  Doesn't look like anyones ever been inside the engine before.  I found half of an oil pressure sensor in the oil pan and a bunch of its little plastic chunks stuck in the balance gears and had jammed up the automatic compression release mechanisms.        

 

I used oven cleaner to get the carbon off the piston and head. Probably can't recommend doing it this way, as apparently it doesn't get along with aluminum.  I didn't leave it on long enough to do any damage but it did make the parts go from shiny to a dull patina.  This stuff is nasty, even outdoors the fumes were choking me.  And it says right on the can not to use it on aluminum. Probably should have read the can first, I'm old enough to know better.

[John G 9]

Finally got the drive pulley off. I've never had anything fight me the whole way like this thing did.  I ended up having to make a puller out of plumbing parts and use an impact wrench along with lots of penetrating oil and a torch.  It would budge a tiny bit at a time, and took several attempts to get it off.

 

The only thing left in the block is the crank bearings.  What's the consensus on replacing those?  The Governor gear was all in one piece and the tab on the cross shaft wasn't broken, so I'm not sure what caused the over-rev.  I still need to do some cleaning and measuring, but the cylinder bore measures almost as new, so I'm not sure whether to have it bored or not.  I'm going to read the Kohler engine rebuilding guide and think on it. 

[pacer 3,159]

Hah! Lovin that "rube goldberg" puller you fabricated - a neat idea!

 

That pulley can sure be a booger - along with steering wheels, flywheels, axle hubs, etc, etc.

[ztnoo 2,298]

2 hours ago, John G said:

Probably should have read the can first, I'm old enough to know better.

 

Absolutely! When all else fails, try reading the instructions FIRST.

 

I'm going to follow this tread like a circling eagle, because I have one of the last series of K341's (installed new in my GT14).

It's 20 years old, but I only use it to mow with. And I have maintained it with regular oil changes.

They are like the tanks of the small, air-cooled engine world for everyday consumer use.

Hopefully I'll be six feet under before my mill gives up the ghost, but one never knows.

 

I love a history lecture, so have at it Professor John G !

 

Regards,

Steve

Edited June 29, 2016 by ztnoo

[John G 9]

58 minutes ago, ztnoo said:

 

Absolutely! When all else fails, try reading the instructions FIRST.

 

 

 

Truer words have never been spoken...which brings me to something I don't even want to admit to having done.  I ended up chipping a good portion of the lip off the welch plug hole when removing it.  Having done this makes me feel really stupid.   To anyone attempting to remove the welch plug: don't try to pry/tap on it to remove it. 

 

 

So I either have to hope it won't leak when I put a new plug in, or weld it up and bore it out on the mill.  I also thought about grinding the rest of the lip off and using a freeze plug.  

 

Here's a clearer picture of the puller I made, the pipe wrenches in the previous post were used to keep the crank from turning when using the impact wrench.  There's two nuts at the end of the bolt and I had a washer between them and the crank to keep from gouging it:

 

Edited June 29, 2016 by John G

[roadapples 6,981]

[MalMac 1,328]

Not uncommon at all to have that oil sensor to come apart and scatter pieces all over. The last two Mag 16's I did had them scattered everywhere in them. I myself do not put them back in. They are nice in the fact that they won't let you start a motor that's low on oil, but the risk of them coming apart is not worth it to me. There again I always check oil before starting at the beginning of the chore to be done with the tractor and after every restart during a job. Maybe over kill on checking but cheaper and less time consuming then a rebuild.

[Horse46 512]

I had the governor fail on mine, part of the balance weight and the roll pin that held it in place were found in the sump. I didn't refit those balance (grenade) gears either, peeps on here suggested they are better left out.

[MalMac 1,328]

If it is a "K" series take the balance gears out. I always have. If it is a Magnum 14 or 16 according to Brian Millers web site they should be left in due to fact that the crank had lighter counter balance on it. The balance gears compensate for the lighter crank. If left out the motor will vibrate terribly. Now with all that said. I left them out of a 16 Mag and had very little if any change in vibration. Now I just rebuilt a 14 mag left them out and had such a vibration I thought it would break something. It was a ultra sonic high vibration. I rebuilt the balance gears new bearing, spacers and put them back in. Problem solved. Miller was not kidding when he said it can cause problems on the 14 and 16 Mags. I'll leave them out on the K's but never again on the big Mags. Made a believer out of me and I am anti balance gears.

[Horse46 512]

OK so is there a MAG K341 as I was referring to my Kolher?

[MalMac 1,328]

No, a K is a K series. Your good to remove the balance gears.

[rmaynard 14,888]

Back in post #2 you asked about the crank bearings. If the ACR and balance gears were all funkdafied with blue plactic, I'd pay real close attention to the crank bearings as well.

[MalMac 1,328]

rmaynard is right on the money. I helped a friend pick blue oil float out of his 16 we rebuilt. It was everywhere including the bearings.