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Kohler Valve Stems


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11-29-09, 05:55 PM   #1  
Kohler Valve Stems

I have a 1989 Kohler 16 hp (MV16S -Type 56511) 950 hours that was having a couple of issues by the end of this season. I found that it had a bad module, and although replacing that definitely helped, it still was running poorly enough that I decided to tear it down and inspect some things per the 500 hour service schedule in the Service Manual. The smoking gun was a defective hose between the crankcase breather and the air cleaner, but I moved on. After cleaning a lot of carbon out of the heads, but determining that the valves and seats looked very good, I did a check on the valve stem clearances. I cannot get a .003-.006 feeler gage between the tappet and the stem per the manual, nor the exhaust valves .016 -.019. Should I pop the cylinder barrels off this engine and do a complete valve job or just re assemble it and leave it alone? It has had great maintenance otherwise, and uses very little if any oil. Advice?

 
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11-29-09, 06:39 PM   #2  
Do you have any clearance at all between the tappets and end of the valve stem?

 
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11-29-09, 07:39 PM   #3  
I'd pull the valves and grind the stems to obtain the proper clearances. I don't recall having to remove the jugs to pull the valves on those engines. I doubt a "valve job" is necessary if the seats and valve faces look good. The clearance issue will make a difference as to how well it runs though. All you have to do is remove the valve and grind, file, or hone the stem squarely and evenly just a hair at a time until the proper clearance is obtained. Be careful to not grind too much away or you'll need a new valve. Be careful to grind it flat/evenly as well, or you could wind up with other problems.

You found a bad breather tube to be causing running problems? A breather tube shouldn't have any effect on the way an engine runs. It is important, however, that it isn't broken or torn though, so as not to allow dirt to enter the engine.


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11-30-09, 07:51 AM   #4  
Kohler Valve Stems

I'm with you a hundred percent. I have a valve spring compressor on my desk right now to attack the valve issue later. I'm surprised at your question about the breather hose connection though. Since I never could get the carb tuned without the air filter being installed on this engine, and since it states in the service manual that a breather tube issue could cause the rough running issues I'm having. (governor hunting, stalling at idle) I just assumed a tight vent hose seal (which I absolutely did not have (the breather tube was pushed completely into the breather/vent assembly and moving back and forth in its access hole) I pulled it out to snap it back into the correct sealed position. Then moved on into the valve clearance checking procedure. Once I get the clearance issue solved, I should be very close to wrapping this one up.

Thank you for your reply!

 
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11-30-09, 08:12 AM   #5  
If you look at how the breather hose attaches to the air cleaner housing, inside the housing, the breather hose is open...free to suck all the air it wants. The important part is that the opening is inside where the filter sits so that all the air available should be filtered. If the hose is not sealed outside the air cleaner housing, it should not make any difference other than the air available is not filtered.

 
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11-30-09, 09:26 AM   #6  
I don't know why the manual would state that unless they were thinking of a blocked/pinched breather hose, which could indeed cause running issues. A cracked or disconnected one would have 0% effect on engine performance though.


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11-30-09, 04:38 PM   #7  
Grinding Kohler Valve Stems

Well I guess the only true test will be to get everything back to spec, and then disconnect the breather hose from the air filter and see what happens. (this hose was shoved quite a ways into the venting chamber, possibly enough to close off the hose at that end) I would have thought that this system would have been designed to suck air INTO the Carb for reburning the vapor rather than going the other way. (Similar to an automotive system?)

 
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11-30-09, 05:28 PM   #8  
Posted By: WML13 Well I guess the only true test will be to get everything back to spec, and then disconnect the breather hose from the air filter and see what happens. (this hose was shoved quite a ways into the venting chamber, possibly enough to close off the hose at that end) I would have thought that this system would have been designed to suck air INTO the Carb for reburning the vapor rather than going the other way. (Similar to an automotive system?)
It does work the same way, it is a crankcase breather, and so will both draw a vacuum and relieve pressure.

 
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12-01-09, 10:51 AM   #9  
It does, that's why unfiltered air can get into the engine...because the hose goes in the air filter housing INSIDE the air filter area where the air passing through to the carb is already filtered.


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12-01-09, 02:10 PM   #10  
Kohler Valve Stems

Well, if it works the same way, I never had an automotive engine that would run right if a vacuum line were disconnected, therefore my confusion on one of the posts where one of you said it wouldnt make any difference....

 
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12-01-09, 02:45 PM   #11  
Posted By: WML13 Well, if it works the same way, I never had an automotive engine that would run right if a vacuum line were disconnected, therefore my confusion on one of the posts where one of you said it wouldnt make any difference....
I think your confusion may lie in your understanding of how an automotive breather functions, and thus your confusion here.

The breather is simply a vent. It does not affect intake vacuum, which is what draws fuel and air from the carb. The breather vents the other side of the combustion,...the crankcase.
The same pressure changes vented by the breather is sometimes used for impulse pumps/fuel pumps on most briggs.

 
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12-01-09, 06:00 PM   #12  
Vent Tubes

That makes sense. When the valve/tappet clearance is correct, the vent will be stock, and I will report back.

thank you all for your comments and help!

 
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12-04-09, 05:45 PM   #13  
Kohler Valve Stems

Well, I didn't get very far. I got one valve spring compressed so I could move the retainer off of its "keeper":.
I thought I might find a roll pin or a "C" clip that I could remove fairly easily. What I found was a steel ring that appears to be pressed onto the valve stem to hold the retainer in position. The ring does not appear to be in a machined groove, and the service manual gives no clues to its removal, or worse yet, putting it back when I'm done. Has anyone worked on one of these?

 
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12-04-09, 09:04 PM   #14  
The norm is the steel outer ring that presses on the valve spring and two little collets that drop into a groove on the valve stem. Those sit on the inside of the ring you're talking about.

When you compress the spring, give a light tap up on the valve itself (hold your hand on the end of the stem to catch the parts). That will push the collets up out of the steel ring and you can remove(or catch) them. Once you get them out you'll see the groove in the stem they seat in and everything will make prefect sense.

 
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12-05-09, 05:34 AM   #15  
Valve Spring Retainer

The steel rings I am talking about are very small. One is located above the spring retainer on the valve stem, and one is located below it. When I compress the valve spring, I can see 3 parts. the coneshaped spring retainer and two steel rings, (I would call them snap rings but they aren't in a grove that I can see, and have no holes for a snap ring plier to work) These are called locking rings and the parts breakdown says 4 are required. The dealer doesn't have any to show me to give me a clue as to what I am dealing with but I have ordered them. Everything is loose around them and they are not budging with minimal force. I may tap it with a punch in the area where the ring is split and see what happens. If there are two pieces of locking ring in a groove I can't see when I do that, everything will be good except the part where reinstalling them comes in.

I know I am getting closer, and thanks for your help!

 
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12-08-09, 07:30 AM   #16  
Kohler Valve Stems

The punch did not budge the locking ring priviously described. there are two rings that almost completely encircle the stem. (they may both be in grooves that I cannot see) one is above the "umbrella" that the spring itself rests in, and the other is above it, both will have to be removed to get the stem out so I can grind it. These rings, whatever they are, are REALLY on there, and need a special tool to remove them professionally in my opinion. I will see what Kohler says about them next.

 
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12-08-09, 08:31 AM   #17  
The "umbrella"...? retainer? Is it slotted where the stem goes through it?
Havin a memory lapse or maybe I've never done valves on a kohler ...but if the retainer is slotted, it should also have a larger opening or hole near the outside of the slot that should slide over the end of the valve stem.
Otherwise try spraying with carb cleaner or brake cleaner...

I found little help in the kohler manuals I could access for photo's or specific instructions...as always, a photo would sure be worth the thousand words if possible.

 
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12-08-09, 10:28 AM   #18  
Kohler Valve Stems

there is no slot in the cone shaped spring rest. Stem just goes straight thru it. The "retainer" rings are located one just above it, and one just below it. These rings will not budge with what I consider reasonalble force. If you send me an email address, I can e-mail you a photo of what I am talking about.

Thanks for your reply!

 
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12-08-09, 11:07 AM   #19  
This doesn't sound like anything Iv'e ever seen on a kohler or any other small engine. Maybe the picture in my mind's eye is not accurate. Have you compressed the spring?


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12-08-09, 04:03 PM   #20  
koh

Well you are not the only one, and yes I have compressed the spring. A photo of it will be available soon for all to see. You will not be able to see the upper one but you will get a look at the lower one. Everyone I have talked to seems to think that there are two pieces to each retaining ring. I won't know that until the replacement kits I have ordered come in, as I cannot budge what is in there with what I call reasonable force.

 
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12-08-09, 10:49 PM   #21  
I'm pretty sure you're looking at regular valve spring retainers. If you compress the spring far enough, the keepers should fall out. Sometimes you have to compress the spring, then tap the valve face to knock it loose from the retainer, then they just fall out.


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12-09-09, 05:02 AM   #22  


I can't tell for certain but it looks like you need to put the spring compressor on the retainer (looks like a big washer) and compress it along with the spring to release the keepers....

 
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12-09-09, 03:49 PM   #23  
Kohler Valve Stems

I see why you would think that, but what you can't see is that the " washer" like part is not pressing on that keeper you can see when the spring is depressed the way it is in the picture. There is actually quite a bit of gap between them. When I compress washer and the spring too, It creates more gap, releases no more pressure on the keeper. Doing that DOES put pressure on the upper keeper though. All I have to do is pop the keeper loose that you can see, the washer and the valve spring will then come down (and off the stem) and then I have to remove the keeper above it (that you can't see) to pull out the valve. The fact that the keepers are so small, (and so tight on the stem) is what my problem is. I have to do this 8 times and I am determined to do it fast, right, and not break anything. As I said before, then I have to put everything back together, and I know that is going to be a challenge too. (Unless there is a special tool, or technique.

Thanks for your help and persistence!

 
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12-09-09, 04:40 PM   #24  
I have to admit to being a bit puzzled even by the photo.
Are those metal shavings or reflection from a flash?
It might be that there is actually some damage and things are wedged however I have not seen that happen.
Perhaps another set of more experienced peepers can determine something more.

 
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12-10-09, 02:09 AM   #25  
Looks to me like you need to get a full grip from top to bottom on the spring along with the "washer" on top so that you can compress it far enough to release the retainers. This looks like a normal setup to me. You don't see the groove because the groove isn't exposed yet. It needs to be compressed fully.


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12-10-09, 01:42 PM   #26  
Looks like you are working on the exhaust valve? Have you tried the other valve?

 
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12-10-09, 03:44 PM   #27  
Kohler Valve Stems

Its the intake valve. The lower valve has a rotator on it, its the exhaust. A local guy thinks that I have the wrong type of spring retractor to do the job right, and is bringing me a different one to try to retract all of the parts and expose the keeper in question. If that does it, I will let you know.

 
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12-11-09, 03:19 PM   #28  
Kohler Valve Stems

Well all you guys get to pat yourselves on the back. The guy who was going to get me a better spring retractor to use couldn't get it to me for the weekend, but was adamant about the fact that the "keepers" were a two piece affair. I had the chance to take a closer look at the bottom of the retainer and turned the "snap ring" around all the way, and there it was, another break in the ring. I ground down a flat screwdriver to be small enough, yet tough enough to pry the part away from the retainer and a quick twist pulled the keeper down and out of the retainer. I had been trying punch the ring in the photo perpendicular to the stem. Not the way! Happy Holidays!

 
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12-11-09, 07:15 PM   #29  
Glad you finally got it! Keep us updated!


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12-19-09, 03:32 PM   #30  
Kohler Valve Stems

A local tech has loaned me a valve grinding kit, and suggested that since I have gone this far, I might as well grind the valve seats , lap in the valves and then grind the stems to the proper specification for tappet clearance. This does not look too tough to do, but since the Kohler manual specifies a 45 degree angle I was wondering about the other two angles that the kit will allow me to grind too. the manual doesn't give specifications for those but the grinding kit has cutters to do two other angles. I watched a training video, which said to grind the other two angles to complete the job. Comments?

 
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12-19-09, 07:24 PM   #31  
Honestly, if the valve seating surfaces and the seats look clean and shiny, I wouldn't mess with them. Valve seating surfaces on small engines usually don't wear enough to warrant re-grinding. You can do it, but there probably isn't need and there is always the chance of messing up. Grinding the valves will throw the clearance off farther, so make sure you set the clearance after the valve job is completely done and they are lapped in as well.

Now if the surfaces look rough and/or pitted, then I'd be more inclined to do it, but usually just a good lapping-in does the job.


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12-20-09, 08:46 AM   #32  
kohler valve stems

Last question. Since the problem that precipitated this whole thing was no clearance between the stem and the tappet, should I grind off some stem to allow the stem some room to go lower still against the tappet BEFORE I start the lapping process?

Thanks!

 
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12-20-09, 09:14 AM   #33  
Do the lapping, then the clearance, although the lapping isn't going to change things a lot.

** Make sure you clean the lapping compound off the seat and valve before you set anything.

 
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12-20-09, 11:14 AM   #34  
kohler valve stems

I will proceed that way. Thanks for your help and have a great holiday!

 
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02-02-10, 06:54 PM   #35  
Kohler Valve Stems

I started a thread a few weeks ago concerning doing a valve job on a Kohler 16 hp opposed twin engine. I wanted to let "cheese" know that I have been putting the engine together for the last few nights after doing a 3 angle grind, a .045 lapping ring on the seats, and a complete refacing of the valves themselves. I fired it up tonight and it runs perfectly. (It never ran this good before)
A few other guys gave advice too, and I appreciate all of the posts.

Thanks!


Last edited by WML13; 02-02-10 at 06:55 PM. Reason: Spelling
 
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02-03-10, 06:39 PM   #36  
Glad you got it and thanks for updating the thread. I moved your latest thread to merge with the old one and complete it.


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