DMedal Posted July 17, 2008 Posted July 17, 2008 During a recent road trip a Kohler M18 fell into my van and rode home with us. The guy I got it from said it uses oil, blows oil, something like that. It came without carb and starter but I've gone to eBay and got those parts. I've not yet even turned this motor over. No holes in the block, it rotates fine, appears to make compression. So... next step: a) tear it down into bits and check it out with the micrometer for rebuild? b) put the carb and starter on and see if/how it runs? c) compression or leakdown test? (I don't have the guage but can beg well) what would you do, especially those of you who do this often? Tear it apart or put it togeter as first steps? if (c), what tests should I be running? thanks for your advice and experience -Don
Willy Posted July 17, 2008 Posted July 17, 2008 If it was mine I would install the carb and starter,get it running just to see how bad it might be. Blowing oil could be from pressure building up in the crankcase. It could be something simple, if not you can always tear it down. Just mho.
Bunky Posted July 18, 2008 Posted July 18, 2008 I have a M-18 thats Smoked and burned oil but was Complete, i'm going to install it and run it.. then tear it down ...
DMedal Posted July 18, 2008 Author Posted July 18, 2008 Bunky- you're going to run it to further diagnosis? I'm going to do as Willy suggests, and hope to avoid a complete teardown. This thing may run a few more years before overhaul. Assuming it DOES blow oil, and there aren't any breather problems, what comes next for diagnostics? -Don
andrewk Posted July 18, 2008 Posted July 18, 2008 I'd do compression and leak down tests first off, to see where things sit internally. There's no use in wasting time trying to tune an engine with bad rings or valves. If those tests looked ok, I'd do a crankcase vacuum test. Basically you want to see if the engine is producing a vacuum. Since it "blows oil" you will probably find that there is positive crankcase pressure. So what you will be looking for is a vacuum leak. Any seal or gasket that leaks air into the crankcase will cause the problem the engine is supposedly experiencing. Dipstick oil seal, crank seals, sump gasket, breather gaskets, etc. Usually the way you diagnose oil coming out the breather is to make sure you have crankcase vacuum, and if you do, the breather is faulty. Hope this helps, Andrew
DMedal Posted July 19, 2008 Author Posted July 19, 2008 Compression I know how to do from doing car engines back when my 7016 was new. Leakdown is new to me. I went looking online for a tool for that and WOW expensive. Is there a poor boy's way of doing leakdown? (like welding an air fitting onto an old plug) My tractor mechanic down the road is building an addition on his house, if I go to ask him I may wind up framing all day. (not a bad thing)
andrewk Posted July 19, 2008 Posted July 19, 2008 I'm not aware of a home brew version of a leak down test. All they really are is a regulator with a pressure gauge downstream of the regulator, so you can see the pressure difference. You need the regulator because you can make an engine pass a leak down test if you use 120psi shop air, as it will force the valves into the seats harder. I think all I run when I do it is 40psi or so, but I'd have to double check the little sharpie mark I made on my tester. However, if compression is adequate, there is no real reason to perform a leak down test, since the valves are part of the compression system. It may add a few days to your project, but the leak down tester is something you could wait on until you have done a compression test. Hope this helps, Andy
DMedal Posted July 19, 2008 Author Posted July 19, 2008 quote:Originally posted by andrewk....However, if compression is adequate, there is no real reason to perform a leak down test, since the valves are part of the compression system. It may add a few days to your project, but the leak down tester is something you could wait on until you have done a compression test.... ok. My regulator is shot anyway. I got the starter on, will do compression test in the morning and post the results. It did seem to turn over a bit too easily by hand. :(
Brent_Baumer Posted July 19, 2008 Posted July 19, 2008 Couldn't find my post from 4 years ago on testing the breather with a homemade manometer (clear tube, water, blue food coloring, a board with water level marked with engine not running, then level with running demonstrating vacuum). Maybe someone else can???? I did find the pics and my followup post on leakdown testing but it is not that helpful: [url]http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=28480&SearchTerms=manometer[/url] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/leakdown.jpg[/img] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/man1.jpg[/img] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/man2.jpg[/img] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/man3.jpg[/img]
gregc Posted July 20, 2008 Posted July 20, 2008 Brent, I believe this may be the topic you were looking for: http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=28014
Brent_Baumer Posted July 20, 2008 Posted July 20, 2008 Thanks Greg. That's the one. I searched for all sorts of keywords that should have found that for me, but alas, no luck. Hope it helps someone. Brent
DMedal Posted July 20, 2008 Author Posted July 20, 2008 compression tested: 90 one side, the other side read 75 first time, 80 2nd time. No real difference after putting a couple of squirts of oil in the cylinder, but I guess it wouldn't necessarily have wound up on the rings. Plugs both black with carbon which easily flakes off, not oily. I can't get a spark but I think I don't understand the wiring on it. Two wires coming out from what I take to be points under the flywheel, but I don't see them opening as I turn the flywheel. So are the compression readings ok, or indicating need for teardown? Thanks for your help, guys. This is my first Kohler that has a chance of running. -Don
andrewk Posted July 20, 2008 Posted July 20, 2008 Sounds like you may have a runner! The two wires should be the stator wires, for the charging system. That engine should have solid state battery ignition. There should be a coil with two plug leads coming off it, mounted on top of the engine. You'll have to have power to the coil before it will spark.
DMedal Posted July 20, 2008 Author Posted July 20, 2008 quote:Originally posted by andrewk Sounds like you may have a runner! The two wires should be the stator wires, for the charging system. That engine should have solid state battery ignition. There should be a coil with two plug leads coming off it, mounted on top of the engine. You'll have to have power to the coil before it will spark. Nope, it has a coil next to flywheel, like a Briggs, with two spark leads out and what I read since is a kill connection. So now I don't know what the 2 leads from under the flywheel are. Everything has connectors that must mate with the missing tractor's harness.
DMedal Posted July 20, 2008 Author Posted July 20, 2008 90 and 80 are ok numbers? The coil turned out to be too simple for my brain - it is a self contained magneto/electronic module. Don't need ANY wiring to it to get it to run. The mystery two leads from under the flywheel are, I'm sure, from the stator. It runs! (just for a bit for now)
andrewk Posted July 20, 2008 Posted July 20, 2008 90 and 80 should be just fine. Glad to hear it runs!
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