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JimD 
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Joined: 11 Sep 2009
Location: Mounds, OK
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 Topic: 712 dies after 20 minutes of hard work
Posted: 13 May 2014 at 10:33pm |
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Ran fine for a while after purchase other than coil going out. Replaced with another used coil I had to get job done. Then have used it for 2-3 hours in a single run.
Lately however after about 20 minutes it will stutter and die. Trying to restart it will hit about every 3rd for 4th revolution, and might fully run until any load is applied. But most often it's a no go for about 1 hr.
Spark is still good when it happens and fuel supply to carb is good. Tried with and without the fuel pump. Carb has been soaked in cleaner, but not actually disassembled and rebuilt. However, I can cover intake, and get wet with fuel.
Compression cold is about 80. When it shut off this evening, I got 40psi. So now I'm thinking a tight valve? How are the valves adjusted on the Kohlers?
Any other suggestions to inspect?
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Owner of OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central. We have new and used parts. 877-378-6543
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Wendell(OK/TX)
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Joined: 12 Sep 2009
Location: Stratford, OK
Points: 546
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Posted: 14 May 2014 at 10:39am |
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Neighbors older Kohler was doing similar stuff. Good job on checking hot compression. Need to check the clearance on the valve to lifter spacing, should be a small cover on the side of the engine. The valve adjustment on MOST of the older small engines was to remove the valve and grind a small amount off the end of it to increase the spacing. Dad had a valve grinder that was set up for doing this, apparently takes some practice so you don't get it too short. Good luck
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farmtoybuilder
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Joined: 11 Sep 2009
Location: Dresden,Ohio
Points: 1453
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Posted: 14 May 2014 at 1:59pm |
Pull head and look at valves. You'll probably find them carboned up and intake valve sticking! You'll need to remove them, clean, grind if needed, reseat and adjust them.
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5 different TT-10's,5 TT-18's Terra Tigers,B-10,2 B-207's,B-110,2 B-112's,HB-112,B-210,B-212,HB212,2 Scamp's & Homilite T-10. Still hunting NICE HB-112 & anything Terra Tiger & Trailers for them.
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Steve in NJ
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Joined: 12 Sep 2009
Location: Andover, NJ
Points: 11566
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Posted: 15 May 2014 at 6:12am |
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Sounds like a valve hangin' up. Might want to try a dose of seafoam in the tank and crankcase and see if will unstick the valve. Other than that, sounds like the engine is okay on specs...
Steve@B&B
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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
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JimD
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Joined: 11 Sep 2009
Location: Mounds, OK
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Posted: 16 May 2014 at 10:18am |
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Well, seafoam did loosen it up. I had fogged engine through carb a while back, and I gave it a healthy dose in the oil. I also loosed up the lash on the valves. Still made it about 45 minutes, and died. IT was late in the evening, and it's the first time I noticed it flaming out the exhaust when trying to restart. So it's a hanging exhaust valve.
Guess the head will come off today.
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Owner of OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central. We have new and used parts. 877-378-6543
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HudCo
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Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3301
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Posted: 16 May 2014 at 10:49am |
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assuming this a kohler 301 check the valve lash when it gets hot everything grows if the lash is to tight and it will not close the valves be sure your coil is internaly resisted
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HudCo
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Location: Plymouth Utah
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Posted: 16 May 2014 at 11:02am |
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you do not have to remove the head to adust valves on the kolher just remove tappet cover couple of end wrenches and feeler gauge intake .008-.010 exshaust .017-.019
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JimD
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Location: Mounds, OK
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Posted: 16 May 2014 at 11:07am |
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Lash was right at spec, so I opened it up a little more to be sure. Yes, it's a K301. It made it 45 minutes of hard work, so it had been plenty hot for a while. I may loosen it up more. It was at .018 and I went to .020
Yes coil is internally resisted, and I have good spark when it dies. But engine spins over too easily, so compression is dropping. 70 cold, and 40 when it dies.
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Owner of OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central. We have new and used parts. 877-378-6543
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JimD
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Location: Mounds, OK
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Posted: 16 May 2014 at 12:58pm |
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Loosened exhaust valve to .022 Ran fine for 30 minutes, then fell flat on it's face. Restart only sputted like before. I'll let it set for an hour, and drive it into shop. Gotta be something hanging up. Still had spark by the way.
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Owner of OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central. We have new and used parts. 877-378-6543
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HudCo
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Location: Plymouth Utah
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Posted: 16 May 2014 at 5:09pm |
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we had a riding mower at our shop last year that would run flawless except when the customer would take it home finnally it would quit after about 20 minets kohler command 15vertical shaft even though customer had changed the fuel filter it would get an air lock in it changed filter and that fixed it also we had a briggs two days ago that would quit because the gas cap vent was pluged
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JimD
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Location: Mounds, OK
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Posted: 16 May 2014 at 5:13pm |
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Yea, I made sure cap was vented. The give-away was no compression while hot, and flames out the muffler.
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Owner of OKtractor.com PM for an instant response on parts. Open M-F 9-6 Central. We have new and used parts. 877-378-6543
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