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ardisam

What causes too much crankcase pressure in a KT19

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ardisam
I'm working a friends Simplicty 7119 and the motor keeps blowing out the seal on the flywheel end of the crankshaft. What would some of the causes for this to happen? Ring end gap was good on the first and second rings, and the pistons where in good condition. Thanks for your help.

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GLPointon
1) Defective breather. If it doesn't open to allow crankcase pressure to escape it will blow out anywhere it can (such as oil seals). 2) A bad bearing will allow crank to move enough to keep damaging the crank seals. 3) Bad rings could allow eenough "blow by" to blow-out seals but I think you could notice the engine running a bit worse??? Good Luck... sm01

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MadMike
I'm going to be keeping an eye on responses to this question. I've recently noticed a very slow oil leak on my 7119H but haven't had a chance to pull the engine and see where it's coming from. I'm not burning oil, just leaking very slowly when parked. Since I can see the front oil seal and the top of the engine, maybe I've also popped the rear seal during a backfire. (I don't always idle for as long as necessary when shutting down) Mike

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ardisam
I took the motor back out of the tractor, and took everything off and reset the oil seal behind the flywheel. I did take apart the breather and found that little rubber piece was not in place. I put it back in place and rotate the motor and found out that there is a lot of crankcase pressure. Now what?

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DanD
quote:
Originally posted by ardisam
I took the motor back out of the tractor, and took everything off and reset the oil seal behind the flywheel. I did take apart the breather and found that little rubber piece was not in place. I put it back in place and rotate the motor and found out that there is a lot of crankcase pressure. Now what?
Replace the breather. There should be a vacuum in the crankcase when the engine is running.

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DanD
If you're just turning an engine over slowly by hand, you'll hear some air escaping past the rings. Otherwise, see point 3 in the second post above. Sounds like the breather is defective anyway. Can replace it and then run the engine before deciding if it needs an overhaul. The breather lets air out of the crankcase, but doesn't let air in. THis results in a slight vacuum being maintained in the crankcase when all is normal.

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ardisam
Dan, read my first posting on here. I said that the ring end gap were good. The motor ran very well. My friend's friend did the overhaul on this motor and he wasn't very good at it, I'm fixing his mistakes. He didn't even replace the fuel pump gasket on this motor, didn't have crankshaft machined. He isn't very well liked in this town, his work is very cheap and charges a lot for his work. What parts do I need to replace the breather? Would be just the little rubber piece?

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DanD
quote:
Originally posted by ardisam
Dan, read my first posting on here. I said that the ring end gap were good.
Read my first post. That's why I said at first you should just replace the breather. Then in a later post you said yourself that you could "hear a lot of pressure in the crankcase" when turning over by hand. Just trying to help you out.

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ardisam
Thanks for the help Dan! I got off the phone with Brett and he was saying the same thing. The motor was pushing out the rubber piece and letting the air back in to blow out the seal. So now I have to get a hold of my friend and tell I need to order a new breather for the KT19. Thanks for all you help!:D

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1Litre
I do not like the seals coming from Kohler the past few years. They are black in color and are rubber covered in and out . I can push them in with my fingers . They move into the bore to easy for me . I had one blow out behind the flywheel on a K series 16 hp . I placed Loctite PST sealant on the bore and placed the seal back in. The sealant hardens like Loctite and retained the seal after that. I looked for aftermarket seals that are the style that are steel on the OD with a thin sealer applied at the factory or just plain steel OD. They require more force to press in but they stay put. Is the bore not worn from a spinning seal from the past?

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ardisam
You usually want the seals from Kohler, they have right inside diameter to fit over the crankshaft. I have found that the aftermarket seal have a bigger inside diameter for the KT series engines. I will always buy seals from Kohler and toss the aftermarket seals in the trash.

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ardisam
I replaced the breather, and put the motor back in the tractor and ran it. It ran really good, but I have a small leakage of oil. I did notice that the oil in the crankcase is over full. I took the motor back out and removed the flywheel, the seal stayed in place. I did notice that there was a little oil at the bottom part of the seal. Would it be leaking oil because the crankcase is over full of oil? Could I put Blue RTV around the seal to make it stop leaking?

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Al
Hi, If you have the new type breather and still have the oil in the breather hose, I am betting that it is time to have the cylinders bored and the crank checked. Sounds like a lot of blow by to me. I have seen this is a lot of these engines. They have very short pistons and when they get tired, have these issues. I am still impressed with the power they provide, to the weight etc. If you keep running one with a lot of blow by, don't be surprised if one day you hear a clank and then you can just look in the crankcase and see the broken parts through the "inspection hole". I firmly believe in rebuilding engines before they have catastrophic failures that may not be fixable. These are very powerful and good running engines, but when they are tired, they usually break a rod and destroy one of the matched crankcase halves. My thoughts, they are free, value accordingly. Al Eden

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ardisam
Al, where did I mention that I had oil in the breather hose? Not to be rude, I didn't say anything about oil in the hose. I said that I had a small amount of oil at the bottom of the seal on the flywheel side of the motor.

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ardisam
I ran the motor again and I still get a oil leak from behind the flywheel. I have made sure that oil level was at the full line, and I put blue RTV around the seal behind the flywheel. My only guess is the bearing is not lined up with the oil channel. Any thoughts?

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GLPointon
If you eliminated #1 from my list than the leak is from #2 or #3. If the crank bearings are allowing the crank to move up&down just a tiny bit that will streach the seal and allow oil to leak past... Also...Don't overfill...at all! sm01
quote:
Originally posted by GLPointon
1) Defective breather. If it doesn't open to allow crankcase pressure to escape it will blow out anywhere it can (such as oil seals). 2) A bad bearing will allow crank to move enough to keep damaging the crank seals. 3) Bad rings could allow eenough "blow by" to blow-out seals but I think you could notice the engine running a bit worse??? Good Luck... sm01

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ardisam
Im going to solve all of your suggestions, the crank, cam, and cylinders are going to the napa machine shop tomorrow. This should have been done last summer when the motor was apart.

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1Litre
That block is split down the middle . I would think that possably the sealer was not applied correctly and the leak is coming threw the mating surfaces. Loctite 518 is good stuff for aluminum flanges on the crankcase. I think the cover on the PTO side is black RTV from Kohler. C/R or National seals are high quality and can be purchased from auto ,truck parts store or bearing warehouse. Good decision to get the cylinders bored so they are strait and true for a good seal. That will give you good service for a long time.

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ardisam
Thanks for the info Ken! I did notice that there was hardly any sealant between the two half's of the crankcase. I have use the blue RTV sealant and never had any problems with it. I just re gasket one of my KT17's and haven't had a bit of oil come out the crankcase or any where else. I will keep your info in mind.

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