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mattd860

Rebuilt Kohler K301 Issues

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So I just started to take things apart and I noticed that the back of the intake cover is all black with oil. To me that means some exhaust might be coming out of the intake valve right?

I will know more as I dig deeper but my kid is crying and I have company over so it's a sloooooooooooooow process right now <_<

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I just took apart the breather assembly again and everything looks fine. The intake valve was clearance was a little tight - about .006", so I loosened it to .010. That seemed to stop the air from backing out of the intake/carb.

However, when I turned the crank by hand, I can still feel pressure coming out of the dipstick tube. This has me thinking though because the dipstick tube is a much easier path of resistance when compared to the breather. So if the dipstick is not plugging the hole, the pressure built by the crankcase (when the piston is in downward motion) will more freely travel out the dipstick tube instead of the breather vent. Am I out on left field on this one? Is pressure only venting out of the dipstick tube because of higher than normal pressure due to blow by?

The kid is sleeping now so I can't test the starting or running of the motor now that I fixed the intake valve clearance but tomorrow I will check all that and let the engine get good and hot. I will also drive it around as best as I can (ice storm tomorrow) to give it moderate load. If excessive pressure is still present then that must mean the rings aren't seated and I will tear it down to inspect them.

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I know your signature says that this is a K301S, but are you positive?

If it is an "S", 2 qts. is correct. If it is an "AS", it's less. Oil pans on the "A" engines are smaller and require the following procedure. Add 1 qt. then add more oil until the proper level is reached on the dipstick. Will be about 1-1/2 qt.

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I went back and looked at some of your pics from earlier posts and it does appear to be a K301S.

2 Qts. is correct.

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I know your signature says that this is a K301S, but are you positive?

If it is an "S", 2 qts. is correct. If it is an "AS", it's less. Oil pans on the "A" engines are smaller and require the following procedure. Add 1 qt. then add more oil until the proper level is reached on the dipstick. Will be about 1-1/2 qt.

I definitely have the K301s with cast iron oil pan bolted directly to the frame (no engine cradle).

I checked the dipstick before I left for work this morning and it reads exactly on the 'full' mark.

I wish it were as simple as too much oil.......

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I am a Tool&Die Maker and a Mechanic. I have rebuilt hundreds of engines and have made a few mistakes over the years.

I have and still do a lot of reading and research on engines because there are many misconceptions involved.

I have read a lot of information that was wrong--IMO.

In ALL material that you read--Remember that this is a person's opinion, just because it is printed doesn't mean it is correct! Just like what I am typing now.

With that being said--I believe you have a blow-by problem caused by--

(1) Broken piston ring?

(2) Incorrectly installed rings--

The SECOND ring from the top is a "scraper". It also is a compression ring. It basically wipes the oil off the cylinder. This is IMO the most critical piston ring in an engine. If installed incorrectly, you will have excessive oil consumption.

The bottom ring is the OIL CONTROL ring--Its purpose is to distribute oil all around the cylinder wall. Note that there are holes in the piston, behind the ring, to allow oil to enter the ring. Look at the way the ring is constructed and it is evident that oil would "leach" around the cylinder wall.

(3) piston rings do not move around a piston, as you stated you read.

I have torn down engines with just a few hours, after a rebuild, and the rings were positioned exactly as they were installed. Ring gap position is important.

Did you check your ring "end gap"?

Please note that these suggestions are merely MY OPINION! I have been wrong many times and I learned from these mistakes.

I try to base all my suggestions on experience--Not what I have read or been told :banghead:

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(3) piston rings do not move around a piston, as you stated you read.

Rings absolutely do rotate within a cylinder.

That is the reason for the locating pins in the ring grooves on a piston-ported two-cycle engine.

If the gap would rotate in line with one of the ports, it could snag and break a ring.

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I think I scored today at my local parts store. I haven't pulled apart the motor yet but I wanted to order genuine Kohler .010 over rings - part # 235890. When I talked to the parts guy he showed one box in stock for half the price. I told him don't bother to go get the box since I was sure it was an aftermarket kit or something but he went to the shelf anyways and picked up a Kohler box with what looks like NOS rings.

Part number 235890 has been discontinued and replaced with 48 108 02-S. But this box has 235890 printed on it so it must be old. I just hope the contents are just as old and not aftermarket garbage. I paid $30 for the rings instead of $80 that part # 48 108 02-S sells for at the same shop.

Take a look at these. I've never seen rings like these before. I am disappointed to see the top ring lined with chrome. Does that suggest they are not genuine Kohler?

P1030330.jpg

P1030335.jpg

P1030336.jpg

P1030337.jpg

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Not to intentionally ruin your day, but there's a HUGE possibility that they won't work with the aftermarket piston.

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Not to intentionally ruin your day, but there's a HUGE possibility that they won't work with the aftermarket piston.

lol you're killing me Terry.

If they don't work then I buy a kohler piston.

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It sounds like your rings didn't seat right . To properly seat rings you need to start the engine , kick the throttle open , and go work it for a couple hours Do not baby it. This is to make the rings seat . When the block was bored was it honed?

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The bore was honed.

Tonight when I got home the engine fired right up - probably as a result of the fixed intake valve. There was still some pressure venting out of the dipstick tube so I attached the plow and did some heavy plowing with the rpms at max for 45 minutes.

After that checked for pressure venting out the dipstick tube and there was still some venting out but not as much. I think the rings are slowly seating.

I would say I'm done with this. I'm going to just run the tractor and enjoy it. I started this endeavor last September due to a loud knocking noise and now the engine runs smooth and quiet.

Thanks to all for their help - I will definitely be keeping an eye on the engine and reporting back with more problems - if any arise.

PS - I would still like to have a wheel horse meet-n-greet at my house sometime this year...........

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Keep in mind that when you remove the dipstick, you are introducing extra air into the crankcase every time the piston travels upward in the bore. That extra air will be displaced when the piston travels downward, leading you to believe that there's an excessive amount of crankcase pressure.

The function of the spring-steel reed in the breather is to allow internal pressure to escape, but stop outside air from being drawn in as the piston travels upward in the bore. The only way it can function as designed is to have an otherwise sealed crankcase.

When you had the breather apart this last time, was the "filter" soaked with oil?

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Keep in mind that when you remove the dipstick, you are introducing extra air into the crankcase every time the piston travels upward in the bore. That extra air will be displaced when the piston travels downward, leading you to believe that there's an excessive amount of crankcase pressure.

The function of the spring-steel reed in the breather is to allow internal pressure to escape, but stop outside air from being drawn in as the piston travels upward in the bore. The only way it can function as designed is to have an otherwise sealed crankcase.

When you had the breather apart this last time, was the "filter" soaked with oil?

The filter was actually dry.

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Did some more plowing of thick heavy slush tonight and it ran like a tank.

It started right up but smoked a little bit. I have tons of marvel mystery oil in the gas - do you think that might be the cause of the smoking on startup? If not oil must still be getting past the rings......

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I would get some fresh gas in there and see what it does.

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I would get some fresh gas in there and see what it does.

Thanks - when I run out of the gas in the tank I will refill it with no additives.

I also forgot to mention earlier that now when I put my hand over the dipstick tube, I can feel my hand being slightly sucked in. I know this isn't the most accurate test for vacuum but at least I know there is some vacuum being created in the crankcase.

Unfortunately I've gotten used to my 418-8 with the electric lift so using the manual lift on the C-81 is a real drag <_<

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From my experience with these engines when black smoke comes out of exhaust to much gas.White smoke means geting oil in gas .Bad rings would cause that. I think you are ok, keep running it in :banghead:

Chas

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I haven't had much time to play with the tractor but over the past couple weeks when I would try to start the engine, it would take a very long time. It will fire with the first turn of the key, run for a few seconds, then stall. After it stalls, it takes about 5 minutes of playing with the choke and throttle controls and endless cranking to get it going.

Tonight after trying to get it started for about 10 minutes, I pulled the spark plug to see if it was drenched in oil or something but it looked clean. Unfortunately, in my stupid haste to get the plug back in I managed to strip out the threads on the head!!

While I wait for a new Head to arrive in the mail, what could be causing the hard starting? I have the timing set at .015 per the recommendations of another rebuild thread. Other than that, everything is by the book. I've tried various settings with the carb adjustments but it usually will only start with the factory initial settings (2.5 turns from bottom on both high and low idle adjustments)

:banghead:

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You said that the plug was clean, but was it wet with gas? Lets talk about the carburetor. I don't see anything about you having rebuilt the carburetor. Did you? If so, what did you do? Did you pull the main jet and needle valve? Did you clean the inside of the needle valve so that all the holes and ports are clear? Is the float and float valve working correctly?

If you haven't purchased a new head yet, you can put in a heli-coil. Just do it with the head off.

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You said that the plug was clean, but was it wet with gas? Lets talk about the carburetor. I don't see anything about you having rebuilt the carburetor. Did you? If so, what did you do? Did you pull the main jet and needle valve? Did you clean the inside of the needle valve so that all the holes and ports are clear? Is the float and float valve working correctly?

If you haven't purchased a new head yet, you can put in a heli-coil. Just do it with the head off.

The plug wasn't drenched. Come to think of it, it may have been somewhat dry but it wasn't completely dry. I slowly backed out the needles about 5 turns while starting but had no success. I know the float needle isn't stuck because it does eventually start and then runs great.

I have rebuilt the carb with just a basic rebuild kit. I also soaked the carb in carb-cleaner. I replaced the float needle, needle seat, and gaskets. The I cleaned the main jet needle but I did notice it was a little bent. When the needle is screw into the carb and sticks out the bottom hole near bottom of float bowl, the needle sits off to the side of the hole. I don't know a better way to describe it.

The butterfly shaft does have some play in it too.

:banghead::thumbs: :ROTF:

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The needle valve should be straight, and all the holes need to be clean. The tube is hollow and must be clean inside. The throttle (butterfly) shaft should not have much play in it. If it does, you will have problems.

Here is a another quote from Brian Miller's web site:

A worn throttle shaft is the #1 cause of most engines wearing out prematurely. If a carburetor has a worn throttle shaft, this will create a vacuum leak and the engine will idle poorly, if at all at times. More than .010" of play is considered too much for throttle shaft wear. Plus, at operating running speeds (3,600 rpms), the extra air will cause the engine to run lean on fuel, which will overheat the combustion chamber and cause the cylinder head to warp and the piston and rings to wear prematurely, eventually resulting in severe engine wear and excessive oil burning.

Brian Miller on Kohler carburetors

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The needle valve should be straight, and all the holes need to be clean. The tube is hollow and must be clean inside. The throttle (butterfly) shaft should not have much play in it. If it does, you will have problems.

Here is a another quote from Brian Miller's web site:

A worn throttle shaft is the #1 cause of most engines wearing out prematurely. If a carburetor has a worn throttle shaft, this will create a vacuum leak and the engine will idle poorly, if at all at times. More than .010" of play is considered too much for throttle shaft wear. Plus, at operating running speeds (3,600 rpms), the extra air will cause the engine to run lean on fuel, which will overheat the combustion chamber and cause the cylinder head to warp and the piston and rings to wear prematurely, eventually resulting in severe engine wear and excessive oil burning.

Brian Miller on Kohler carburetors

Thanks for the tips! I have been mulling over the idea of getting a new carb for a while now. I guess I'll get one now. I will also have the head checked for warpage. I'm not leaking oil or exhaust (as far as I can tell) but it can't hurt to find out.

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