Kohler K241 Crankcase Breather

[tunahead72 2,412]

I need some help with this.

 

I've spent a lot of time tweaking my 1986 310-8 and Kohler K241 this spring, thanks in large part to all of the helpful information I've found in this forum.

 

One of my current issues is a couple of very minor oil leaks that seem to indicate a possible crankcase breather problem, the first around the governor shaft, the second from one of the cylinder head bolts. I tightened the large bolt around the governor shaft VERY slightly, and it seemed to help a bit, but not completely, and I don't know how much more I can tighten it without causing problems. I also replaced the head gasket earlier this year, torqued the bolts to 30 ft.-lbs., and retorqued cold twice since then, and still get a little bit of oil leaking out around what's labeled as bolt #4 in the service manual (right rear corner of the head).

 

So, I decided to look at the crankcase breather, something I've never done myself on this machine, and I suspect it's installed incorrectly because it doesn't match any of the photos or diagrams I've seen anywhere.

 

I have lots of photos:

 

The first 3 pics show the cover, the first still installed, the next two after being removed. So far so good, I think, the opening was basically clear, a little dust around the edges of the gaskets, nothing I thought was unusual. I did tighten the nut one day last week, but only a little because it seemed like I might have been bending the cover, so I stopped.

 

 

 

 

Here's where it might get goofy. This is how it looked after I removed the cover. You can see the first gasket, mostly intact. After this, the next 3 items I removed, in order, were the baffle (installed backwards?), the filter, and the seal (which was squished between the filter and the reed). The diagrams I have from the K241 service and parts manuals both show these 3 pieces in exactly the OPPOSITE order from what I found.

 

 

Here's the baffle, the filter, and the seal and reed, all OK I think:

 

 

 

 

And the inner plate. You'll have to look carefully to see that the drain hole is on the bottom as it should be, but it's almost completely blocked by the gasket!

 

 

It's hard to imagine this system is operating properly with a clogged drain. Could it also be creating excessive pressure in the crankcase, which would possibly force oil out around the areas I'm seeing leaks?

 

My plan right now is to clean things up better, clear the drain, replace both gaskets and put it all back together. Main questions: what is the correct order to reinstall these parts, and is there anything else I should replace besides the gaskets?

 

Actually, there's one other thing I plan to do while I'm at it, which is check the valve clearances. I've seen the instructions in the service manual, but I've never acually done this before -- I assume I can rotate the engine by hand by rotating the grass screen / flywheel, how do I know when the piston is "at the top of the compression stroke"? And will it be obvious how to turn the adjusting screws?

 

Thanks guys, I can't say enough good things about this forum!

[rmaynard 15,459]

Looks like it's assembled wrong. Take a look at the diagram below. The filter goes in after the baffle.

 

 

Adjusting the valves is easy on that model. You can rotate by hand, and yes, it will be obvious when the piston is at TDC compression. Just rotate until both valves and lifters have space between them, or you can check the sight hole in the blower cover and line up the "T" mark. Chances are you won't be able to see it due to dirt, so just do the first method.

 

All you need to adjust is a set of flat feeler gauges, and I believe a 1/2" and 7/16" open end wrench.

[MalMac 1,331]

I just rebuilt a K241, as the diagram in prior post shows the baffle is in wrong side facing engine and the filter is on the wrong side of the baffle. Looks like the way it's assembled in your Pic. it would be very restrictive in letting out crank pressure.

[tunahead72 2,412]

Thanks for your quick response guys, that all makes a lot of sense to me.

 

Bob, your diagram is exactly one of the ones I looked at, looks like Fig. 12-46 from the service manual. Is the rubber seal supposed to slide inside the filter? I don't remember exactly, I think mine was jammed up against the reed, didn't look right at all. I just ran across something that Terry (TT) wrote a while back, I think I'll go ahead and replace that seal while I'm at it.

 

The valve adjustment seems straightforward enough, I actually think I have half a chance of seeing the "T" mark inside the sight hole, I noticed the "S" mark there the other day when I was adjusting the points.

 

Thanks again, I hope to get parts today from my friendly NAPA guy, I'll let you know how it works out.

[rmaynard 15,459]

tunahead72 said:

Bob, your diagram is exactly one of the ones I looked at, looks like Fig. 12-46 from the service manual. Is the rubber seal supposed to slide inside the filter? I don't remember exactly, I think mine was jammed up against the reed, didn't look right at all.

 

The baffle plate goes in with the center part right up against the reed. Then the filter goes into the recessed area of the baffle plate with the rubber seal going into the center of the filter. Make sure that you straighten the baffle plate. It appears to be bent a little.

[MalMac 1,331]

B-100 Bob is dead on 100%. Straighten that baffle plate out. Make sure reed is flat also.

[tunahead72 2,412]

Thanks again, both of you. I wouldn't have known the baffle needed to be flat, I should be able to bend that back into place. I assume that means the inside and outside faces need to be parallel? And why does it need to be flat exactly?

 

I think the cover plate also needs to be straightened a little -- it's pushed in kind of like the baffle, right at the center where the nut tightens down, I probably didn't help that situation when I tightened the nut the other day.

 

I think the reed is OK, but I'll check it again.

 

[rmaynard 15,459]

tunahead72 said:

I assume that means the inside and outside faces need to be parallel? And why does it need to be flat exactly?

 

When the center section of the baffle plate is sitting on a flat surface, the "wings" should be parallel to the surface. I'm not sure why yours are bent, but they should not be. The reason? That's the way Kohler engineers designed it.  It probably has something to do with airflow.

[tunahead72 2,412]

This is actually starting to make some sense. It seems like there has to be good airflow both behind and in front of the reed, so it can react to changes in crankcase pressure and let excess pressure vent to the outside. The way mine was installed, the reed was restricted by the baffle wings pressing up so close to it, so it couldn't vent properly. Good theory, anyway, we'll see how it all works after I get everything straightened out and installed correctly.

 

Which reminds me, this keeps getting weirder. I took a closer look at the inner plate, especially at the back/engine side. There's supposed to be just a simple "thick paper" type gasket between this plate and the engine. Mine has instead what looks like a thick bead of sticky black caulk along the outer perimeter, and it's this junk that's blocking the drain hole. Quality installation, huh?

 

Here's a photo of what I'm talking about -- pay no attention to the blue area that you see in the middle, it's just something I used to prop up the plate for the photo:

 

 

To be continued....

[rmaynard 15,459]

If you have a NAPA store close by, they can get you the proper gaskets.

 

NAPA part numbers SME 702501 & SME 702500.

[tunahead72 2,412]

I'm back....

 

I've adjusted my valves -- the intake was right on at .009", the exhaust was a little tight at .016", adjusted it to .018". Bob, thanks for the heads-up about using TWO wrenches, I wasn't getting that from the low-quality photos I had to work from.

 

I ran out of light today, but I did manage to clean up all the breather parts, and straighten the baffle and cover plate. I also have new gaskets and a seal, ready to put it all back together tomorrow when I can see better.

 

The gasket on the inner plate turned out to be a rubber-like material, with an extra bead of black caulk around the edges. Bob, those NAPA gaskets you mentioned are exactly the same type of "thick paper" construction as the Kohler gaskets I bought.

 

We'll see how this all comes together tomorrow -- we need a "cross your fingers" smiley, or maybe "praying" or "knock on wood".

 

--------

 

A couple of theoretical questions (I'm curious, I may start a new thread):

 

I have two early '80's Honda motorcycles. The service manuals for these mention that valves should be checked and adjusted early in any kind of engine troubleshooting process, or in any spring maintenance routine for that matter. They suggest that until the valves are known to have the correct clearances, any compression checks or timing adjustments or carb adjustments will give unreliable results. I know we can get some useful information from these tests and adjustments even if the valves aren't perfect, but does the same advice apply to the engines used in our Wheel Horses?

 

Also, I know it's not generally a good idea to have valve clearances that are too tight, but is there any advantage to keeping them slightly loose? Other than a little extra noise, are there any disadvantages?

[rmaynard 15,459]

If the valves are adjusted too tight, there is no room for expansion when they get hot. Keep them at the Kohler specs.

 

Checking compression on the Kohlers is not easy since they have ACR (automatic compression release) to assist in starting. The engine has to be turning at about 600 RPM before the ACR kicks out and full compression can be read.

[tunahead72 2,412]

Before I put this section of the puzzle back together, can somebody tell me what is the little hole located just below the bottom right corner of the valve/breather opening (as you look at the opening)? I just noticed it today, it's wet with oil inside, and I don't know what it's for. I see it in Figure 3-10 of the Kohler K-series service manual, but I can't really tell anything from that photo. It may be threaded, just can't tell for sure, and it's between #10 and 1/4" in diameter.

 

The only thing I can think of is that maybe it's a spot for another throttle cable clamp, but I'm just guessing here. Just to avoid some possible confusion, this engine has a newer Walbro adjustable carburetor, not the original Kohler, and the cable may not be routed exactly by the book.

 

Here's a couple of my own photos, any ideas?

 

 

 

Thanks!

 

--------

 

I'm so sick of this rain -- 6 freakin' days in a row!

[tunahead72 2,412]

I decided the little hole wasn't anything I needed to be concerned about -- it does appear to be threaded, maybe for a screw/bolt for a cable clamp or some kind of bracket, the oil cleaned out easily, maybe was just seeping from the valve cavity above while I had it open.

 

I reinstalled the breather, in the correct order with everything facing the right direction, installed the carb, rerouted my choke cable a little, adjusted the governor and started it up, and it seems ... fine. Not a huge difference, I'll know more tomorrow when I run it longer, no obvious leaks, maybe a little smoother.

 

I'm a little concerned that I'm not feeling the little pulses of air that Terry (TT) mentioned in another post, exactly 3 years ago to the day. I didn't tighten the breather nut down nearly as tightly as it had been before, so there may be more air leakage around the perimeter of the breather assembly, maybe those "pulses" are exiting more uniformly around the edges? It's a guess.

 

I'll check in again tomorrow, thanks everybody!

[tunahead72 2,412]

Well, THAT didn't work.

 

I started her up this afternoon, and now I'm getting a steady stream of oil seeping out from the bottom edge of the breather assembly.

 

The only thing I can think of is that the cover plate isn't making good contact with the gasket. I had already straightened it quite a bit because it was bent inwards in the stud/nut area, maybe it was just too far gone for that to work. I tried tightening the nut a little more, it didn't make any difference.

 

I'm planning to replace the cover plate and both gaskets, and see what happens, anybody have any other ideas?

[TT-(Moderator) 1,131]

Did you use any kind of sealant on the gaskets? (like Permatex, etc.)

[tunahead72 2,412]

TT said:

Did you use any kind of sealant on the gaskets? (like Permatex, etc.)

 

No, I didn't, but I'm willing to give it a try -- any version of Permatex in particular? And would I apply it to all of the gasket surfaces?

[TT-(Moderator) 1,131]

"Ultra-Black" is what I normally use.

 

A very light coat on both sides of the gasket should do the trick - unless things are bent beyond being able to seal.

 

Make sure the oil drain-back hole in the block is open too. (back between the lifters / valve springs)

[rmaynard 15,459]

In the one picture, and you mentioned it, there was a bead of some type of sealant on the cover and the breather plate. That leads me to believe that someone had the same leakage problem previously, and attempted to correct it with sealant. Hmm...

 

First, check to be sure that the drain hole is open. Then check your gaskets.

 

I don't think you are getting a good seal on your gaskets. If you take all the components off again, take the breather plate and lay it on a flat surface. It should lay perfectly flat with no gaps. The cover should do the same. If you can't straighten them, maybe you should try to find some better ones. Because the cover is vented, there should be no pressure build-up in the breather area. Therefore, all the oil is coming out by gravity. Getting a good tight seal should stop it.

 

Edit: Oops...while I was out getting my thinking cap on, TT beat me to the drain hole theory.

[tunahead72 2,412]

Thank you, gentlemen, I'm trying to get this resolved this afternoon before the skies open up again, I appreciate your quick responses....

 

I just picked up some Permatex #2 that I thought might do the trick -- would the Ultra-Black be a better solution?

 

I'll check both plates -- I believe the inner plate is fine, but the cover is definitely questionable.

 

I'll also check the drain-back hole -- it looked OK earlier, is it safe to poke it gently with a small wire to make sure it's clear?

 

Yes, the guy who rebuilt this engine 2 years ago left the breather this way for me. I would talk to him myself, but he closed shop and left town shortly after that -- I'm just happy I got my Wheel Horse back before he did that, some of his customers apparently weren't that fortunate.

 

A couple of related questions:

How much should I tighten the nut?

When this system is working perfectly, how much of a "pulse" of air should I feel out of the vent? -- I'm not feeling anything right now.

 

Thanks!

[TT-(Moderator) 1,131]

Permatex #2 is the "Form-A-Gasket" stuff, correct? That should be fine.

 

The retaining nut only needs to be tight enough to hold the breather assembly to the block and seal the gaskets. If the outer cover was dented in, then it was WAY too tight.

 

You can run a wire through the drain-back hole without fear of hurting anything.

 

As far as feeling pulses out of the breather vent hole.............

Ideally, if an engine is "fresh" and/or well-sealed (including rings) you shouldn't really feel much of anything being blown out of the breather.

The actual crankcase pressure differential should be measurable vacuum to zero (atmospheric pressure) if everything is working the way it should. That's enough of a difference to make a pulse-type fuel pump work, (like used on newer engines) but there shouldn't be any slobbering or drooling from the breather.

Once valve guides, rings, etc. wear enough to allow cylinder pressure (compression) to enter the crankcase and/or gaskets and seals start allowing "extra" outside air to be drawn in to the crankcase, then that's when the excess air has to be forced back out when the piston moves downward.

[tunahead72 2,412]

TT said:

Permatex #2 is the "Form-A-Gasket" stuff, correct? That should be fine.

Yes, it is -- "non-hardening pliable sealant" according to the label.

 

Quote

The retaining nut only needs to be tight enough to hold the breather assembly to the block and seal the gaskets. If the outer cover was dented in, then it was WAY too tight.

Yeah, that's what I thought, I see all kinds of gaps around the edges of the cover, even after I straightened it. I'll replace that, unfortunately it seems to be available only as an assembly with a new baffle and filter -- oh well. The inner plate seems fine, nice & straight, no gaps.

 

Quote

You can run a wire through the drain-back hole without fear of hurting anything.

Did that, hit something very solid within about 1/2" or so, the hole itself is clear.

 

Quote

As far as feeling pulses out of the breather vent hole.............

Ideally, if an engine is "fresh" and/or well-sealed (including rings) you shouldn't really feel much of anything being blown out of the breather.

The actual crankcase pressure differential should be measurable vacuum to zero (atmospheric pressure) if everything is working the way it should. That's enough of a difference to make a pulse-type fuel pump work, (like used on newer engines) but there shouldn't be any slobbering or drooling from the breather.

Once valve guides, rings, etc. wear enough to allow cylinder pressure (compression) to enter the crankcase and/or gaskets and seals start allowing "extra" outside air to be drawn in to the crankcase, then that's when the excess air has to be forced back out when the piston moves downward.

That makes a lot of sense, and explains (I think) why I'm not feeling anything out of this engine, which theoretically at least is pretty tight. It'll be interesting to do the same check on my other Wheel Horse, a C-105 also with a Kohler K241 -- that one was rebuilt about 10 years ago, and I would expect it to be a little looser.

 

Thanks again guys, I may be able to round up a cover tomorrow and get this back together again, I'll let you know how it turns out!

[tunahead72 2,412]

Waiting for parts.

 

Now mowing an acre with a push mower, just happy it's running well.

[can whlvr 993]

i was just reading your topic and i have a question,is it a k241 or a magnum12,not that it matters for the oil leak as they are the same block,its just that my 1986 308 is a magnum and its black,i know they went from k to magnum in 86 so maybe yours is a k,just curious,

[TT-(Moderator) 1,131]

The 308 models got the Magnum one year earlier than the rest of the tractors. 1987 was the first year for Magnums on the 310. 312, etc.

 

With a few exceptions, regular use of "black engines" began in 1980.