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Overhauled Koh M18 oil consumption


Al

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Hi We have a customer that uses a pressure washer with a M18 Koher every day in a hog confinment operation. We sold him a new M18 and rebuilt the old one to set on the shelf as a spare. The new one had a valve burn and it came in and the old one went on line. The one we overhauled used an unbelievable amount of oil. As soon as the new one was fixed I received a present back. I did not do the work on this engine and the person that did no longer works for us. When he did the engine, I questioned him and specifically asked him if he had scrubbed the cylinders with soap and water when he built it and he assured me that he had. I checked some other details as he did it, and always got the correct answers. Now I have this engine that we did 3 yrs ago back using oil. Since it sat so long and when they started using it it wasn't right we assumed responsibility for it. My worst fears were that he hadn't scrubbed the honing grit out with soap and water as he said, and had instead used solvent. Then we would have had to tear it completely down and replace anything that wasn't perfect at our expense. Anyway we put it on the test stand and started a systematic test on it. It had good compression and ran beautifully. Next I connected a manometer to the crankcase and the crankcase vacuum was 0 at full throttle. Interesting. Next step, do a leakdown test on each cylinder, perfect. Thank goodness. Next step pulled the crankcase breather off. NO RED RUBBER SLEEVE THAT FITS ON THE STUD THAT HOLDS THE COVER ON. This tube seals the reed plate where the stud goes through to hold the cover on. Without this little piece the reed valve did nothing as air could flow in and out around the reed plate as easy as if the reed was gone. Put the rubber in and reassembled breather, ran engine crankcase vacuum good. The oil consumption was caused by the air leak into the crankcase. My worst fears of an expensive come back turned out to be a cheap fix. I am sharing this to demonstrate the value of testing in a logical manner find problems before tearing things apart. We could have torn this engine down and put new rings in etc, and put it back together and it would have run the same and still used oil. I might mention that the rubber tubes on the air cleaner studs are for the same purpose to seal air cleaner studs so dust don't get in. Some air filters come with these "tubes" and when they do the old ones should never be reused. I am resting a lot better tonight, because we proved the failure and fixed it. Just goes to show that no matter how much one tries to be fail free, things happen. Thought some you might not feel so alone. We all cry sometimes. Al Eden
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Al, do you routinely test all high oil use engines brought in by your customers? It seems the reason for testing was to avoid "replace anything that wasn't perfect at our expense". I'm sitting here wondering, after reading about this extensive test, how many engines were rebuilt unnecessarily by dealers simply because nobody would perform all these tests. There would be no motivation to test a customer's "worn out" engine. It seems entirely possible for a reputable repair shop, even one as good as Al's to have done many rebuilds on engines with high oil usage symptoms. How many disreputable repair shops fixed the air leak and charged for more extensive repairs? I will continue to repair my own engines.
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Hi, We knew this engine would set and did for a couple of years. We also knew the customer was honest about usage. We also guarantee our work, and this customer deserved getting what he paid for and we didn't give him. These tests take all of 15 minutes to do. If we have an oil burner, this is the route we take. First off the spark plugs looked good. As I have posted in the past, carankcase leaks and breathers are responsible for a lot of oil consumption. It takes so little time to measure first and know where you are going. If the crankcase vacuum had been good and the leak down good and compression good, next I would have pulled the head and looked at the tops of the pistons to see if there was one cylinder that showed oil washover. If one were oily around the outside, we would have pulled that jug and checked for a broken expander in the oil ring. This will cause excessive oil washing and will not affect the compression or leak down. Ususlly you see a clue from the plug on the bad cylinder if that happens. One of the hardest things to do in a shop like ours, is to train mechanics not to jump to conclusions, but test first. This is particularly true in things like chain saws. Most mechanics like to jump to conclusions and throw a carb kit in a chain saw and when that didn't fix it, then pressure check the fuel pick up tube and fuel filter, the carb diaphram pop off and then finally pressure test the crank case. When in fact it takes a lot less time to test first and have a target to hit when you pull the trigger. All of the carb kits in the world won't fix a saw with a crack in the fuel pick up tube. Believe me I know this runs against the grain of so many "mechanics" one hires as they all want to think they can sense all of the problems. We sell Stihl and Stihl spends tons of money in training to teach people how to analyze and this mentality is changing. Thanks Al Eden
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quote:
Originally posted by Al
Next step pulled the crankcase breather off. NO RED RUBBER SLEEVE THAT FITS ON THE STUD THAT HOLDS THE COVER ON. This tube seals the reed plate where the stud goes through to hold the cover on. Without this little piece the reed valve did nothing as air could flow in and out around the reed plate as easy as if the reed was gone.
Very interesting. Earlier this year I bought a used tractor with a KT17 Series II. The engine, battery, and fuel tank all had a film of oil on them. The previous owner had put on a new vent tube to the air cleaner. I decided to determine where the oil was coming from. There was caked on oil on the cylinder fins which indicated that it had been leaking oil for some time. I pulled the muffler and found the exhaust gaskets shot. I pulled the LH valve cover and found two gaskets (sort of) under the valve cover. This might have been responsible for some of the oil leaks. I pulled the RH valve cover and found the gaskets to be pretty rough and stuck hard to the valve cover. The reed valve was cracked and the broken part had found its way down by the valve springs. There was no rubber sleeve on the valve cover stud and there was no breather filter. I'm convinced that the combination of the broken reed, missing rubber sleeve, and missing breather filter were responsible for blowing oil out onto everything when the breather tube was missing. We'll see as soon as I get the engine back into the tractor and start it up. Thanks for the insight.
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quote: I could be wrong but I think you were a little critical of him shareing some of his expertise. I asked a question of Al based upon what he wrote. quote: It seems entirely possible for a reputable repair shop, even one as good as Al's to have done many rebuilds on engines with high oil usage symptoms. Was I picking on Al here? NO, you are wrong as you surmised. Around here nobody (repair shop) would test an engine in the way described.You will pay for a rebuild. That's not to say the individuals in the repair shops aren't friendly to talk to, just they don't look a gift horse in the mouth. I trust myself more than the repair shops. I will continue to repair my own engines.
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Hi, I didn't post this to create problems. We stand behind what we do. As I tell people that work for me, the only people that never make a mistake are the people that never do anything. We made a mistake here, and as I delved into it, I thought that the process I used and how I determined the problem might be of interest to some of the people here. We try very hard to "not pile cost on work we do". Often it bites us. My guys will sometimes come and say what do you think about this? I may look and say: "Well it isn't all that bad, but not that good either, but looks like it ought to go another season". It seems like when I do that a week later it fails and we eat the labor to replace it. I would have been better off to just put it on and be paid for it in the first place. When you are in our business, the worst thing that can come in is a $300.00 tractor. The reason it is,is that it needs 1500.00 worth of fixing. The owner doesn't want to spend any money on it and so you fix the catostrophic problem and that is all that they want. Once you have your fingerprints on it you own it. You put a needle and seat in the carb, and next week the trans don't shift and "I didn't have any transmission problem before you worked on it. There are many very good and ethical dealers out there and they stand behind what they do. There are also some undesireables out there, just like in any other profession. If you work in a factory, you know there are people that go in and are valuable employees, and those that go in and almost complain that the company doesn't have a courier deliver their check, then they wouldn't have to go in, and the company might even be ahead if they didn't. Enough! I am the first to say that we are human, we make mistakes, we stand behind them, and we are willing to admit them. I post these things in the hope that they will benefit someone else. Its kind on like the minister in church asking the congregation to raise their hands if they thought they were going to go to heaven. One guy didn't raise his hand. The minister asked him why he didn't. He said he only knew of one person good enough to get there and that was his widowed wifes first husband. We ain't that good. Al Eden
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QUOTE: "Most mechanics like to jump to conclusions and throw a carb kit in a chain saw and when that didn't fix it, then pressure check the fuel pick up tube and fuel filter, the carb diaphram pop off and then finally pressure test the crank case. When in fact it takes a lot less time to test first and have a target to hit when you pull the trigger. All of the carb kits in the world won't fix a saw with a crack in the fuel pick up tube. Believe me I know this runs against the grain of so many "mechanics" one hires as they all want to think they can sense all of the problems." Do you,D-17_Dave, see the word "MOST" up there. Al seems to know what's out there as evidenced by his example quoted above. I know what's out there. You, D-17_Dave, don't know what's out there. Al stated to my satisfaction, as if it mattered what I think, that he does indeed test his customer's engines. I learned something from Al's post as I have in the past.
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I knew nothing about these machines other than that I had owned one for nearly 20 years when I found the site. I've been extremely lucky to have benefited from the willingness of knowledgable people to share information through this forum. Thanks Al, for taking your time to share your diagnostic approach. Kent, can we get Al's post copied to the Resources/Technical Tips section?
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Al you are so right about the "$300 tractor". I would guess even with limiting our shop work to our lines(Simplicity,Kubota,Cub Cadet,Toro,Xmark,Honda and Stihl) much of our service work is on the older,hanging on till next season equipment. And you're right, once you touch it you own it. We even go so far as to state on the service ticket that work performed is stop-gap and state what it will take to make proper repairs. That doesn't make a dang bit of difference either. But life goes on....
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Take note: I have mentioned this before to people with boxer twins (KT17, KT19, M18, M20) that are burning oil. They are notorice for their "breather" problems. I have another KT17 series II that gets the air cleaner and carb intake full of oil. And I have been through the breather 3 times now.
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Hi, Are you using 10W-30 oil? These engines can destroy multi grade in the Summer. If you are Put in SAE 30 and if the engine is in good shape oil consumption should go away. My first 7117 demo my first year as a dealer, I put 10W-30 in, oil RAN through it. I got the owners manual out and AS STATED gave it straight 30 and the problem left. See I am a model of imperfection, i just try to remember all of my learning experiences in the school of hard knocke. Al Eden
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My KT17 is missing the air tube from the fan housing to the air filter housing (hose no longer available from Kohler). Could I be pulling too much vacuum in the carb area, without the air tube? When I disconnect the breather tube from the valve box I do not seem to get any oiliness on top of the valve box and of course no oil in the air filter/carb.
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thanks for the info Al, it will help in doing our own work, and appreciating others good work. Hope business stays good, if you keep running things like you do...it will.
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Another great tip Al! Thanks for your efforts! I've been an Electrician for 37 years, and know proper trouble shooting technique is key to success.
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