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 | rgpbeme
Join Date: Mar 2006 Posts: 55 Eureka Springs AR 
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2006-10-24 136279
Hi I have talked about my little B7200 before I wanted to know what causes blow by. Mine blows alot. It is worse at idle. I even have some oil drops coming out the tube. The tractor runs great has plenty of power and the exhaust is clean. The oil is at the right level and it uses hardly any oil. You can pinch the overflow tube and it will blow the dip stick out
Thanks Ron
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 | earthwrks
Join Date: Dec 2003 Posts: 3853 Home Office in Flat Rock, Michigan 
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2006-10-24 136281
Sounds like a worn or broken piston ring. I had a skid steer that did that and ran OK with blow by for about a year or so then worsened to the point oil was dripping out at a such at rate I was losing a quart a day.
Does it smoke before it warms up? ....
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| rgpbeme
Join Date: Mar 2006 Posts: 55 Eureka Springs AR
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2006-10-24 136283
yes it does . It seems to smoke more when on a angle It dosen't smoke as much when running at higher RPM.
It has only had a drop or two of oil come out ....
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| earthwrks
Join Date: Dec 2003 Posts: 3853 Home Office in Flat Rock, Michigan
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2006-10-25 136287
I dunno about yours but mine dripped oil AND it was being sucked into the intake (air cleaner) and collected there. If it's whiteish grey smoke it's oil, blackish brown is fuel. ....
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2006-10-25 136288
I'd be checking the air cleaner and more then likely replace it.. From past experience it is a problem with ring leakage past the rings. This could be from wear or cylinder glazing. The wear part needs new rings in a rebuild. The glazing is from unburnt or partially burnt fuel from running an engine to cold. This can be cured by warming the engine better and working it hard to reseat the rings if the condition is not to severe oter wise you are back to the reringing process. ....
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| bewing
Join Date: Jul 2003 Posts: 35 kingston springs tennessee
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2006-10-25 136314
Where do you find this tube you are talking about? I have an older Bobcat 743 that puffs a little white smoke for 2-3 seconds when it first starts. It doesn't seem to burn any oil and after it starts it runs clean unless it is under a load and it smokes a little. WHat tube are you talking about and does my B7500 Kubota have a blow by tube too? ....
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| rgpbeme
Join Date: Mar 2006 Posts: 55 Eureka Springs AR
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2006-10-25 136315
Hi I don't think it is a blow by tube. It is the vent tube that comes off of the valve cover. Blow by is all the smoke that is coming out of the vent tube. ....
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| bewing
Join Date: Jul 2003 Posts: 35 kingston springs tennessee
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2006-10-25 136316
Thanks for your comments. It sounds like if I do not have any smoke coming out of the tube on the valve covers or alot of pressure I should be ok?
Is this tube on the valve covers there to bleed off unwanted pressure in the valve cover area? ....
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| hardwood
Join Date: Dec 2002 Posts: 3583 iowa
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2006-10-26 136317
Bewing; The tube coming from the valve cover is to relieve crankcase pressure. It should be checked periodicly to be sure it is open, engines have been ruined because of a cloged blowby tube. When it is completly plugged the pressure from blowby has to go somewhere so usually it pushes oil past the main bearing seals, valve cover gaskets, etc. A little blowby is normal even a new engine has a little. Best of luck. Frank. ....
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| earthwrks
Join Date: Dec 2003 Posts: 3853 Home Office in Flat Rock, Michigan
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2006-10-26 136318
bewing on the Bobcat it's normal to have a few puffs of grey smoke---that's unburned fuel. It should go away after it warms up. If you restart it while warm it isn't there right? Vent tubes from my experience don't have to go all the way up to the valve cover; sometoimes they will come out the side of the block. Their purpose is to vent the crancase either to the atmosphere directly or recirculate it to the air cleaner (diesels) or to the intake through a PCV valve (gas) ....
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| rgpbeme
Join Date: Mar 2006 Posts: 55 Eureka Springs AR
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2006-10-26 136323
I can't read all the message. I don't have enough equipment to join full acess
Thanks for the comments
ArtW The tractor has a new air filter. Is there some additive I should use to help reseat the rings I don't use the tractor enough to buy a rebuild The tractor is new to me I always warm it up. and cycle the loader cylinders several time befor use ....
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| Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2006-10-26 136337
What we do to help get the rings to reseat is to be sure the tractor is getting up to temperature. Then we load or overload it with the dyno for a couple of hours to bring everything to it's best. We've seen 100 horsepower tractors gain 20% horsepower when they get reseated. We've seen some that had been run to long with the cold running and with four or five hours on the dyno they still wouldn't come back. Your tractor has a syphon cooling system and often the owners didn't get them up to temp to break-in properly. ....
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| bewing
Join Date: Jul 2003 Posts: 35 kingston springs tennessee
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2006-10-26 136358
earthwrks you are correct right after the engine starts the white smoke goes away. There is a little blackish smoke coming from the exhaust when it is under a load but nothing excessive. I will look to see if I can find the tube and check it and make sure that it it clear for preventative maintenance if that is a good idea. ....
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| earthwrks
Join Date: Dec 2003 Posts: 3853 Home Office in Flat Rock, Michigan
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2006-10-27 136363
bewing if you don't have an intake grid- or glow-plug type heater then I think you have a normal condition of grey smoke going away. If you do have a heater system and it's not working you might want to fix it as it allows the engine to start almost immediately reducing starter wear and increasing battery life. ....
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| rgpbeme
Join Date: Mar 2006 Posts: 55 Eureka Springs AR
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2006-10-27 136367
Mr White thanks Your message was cut off a syphon cooling. What was after that. What is a good way to load the engine in the field? Whould holding the loader valve or raising the 3-point and keep it on work? I can't believe the power the little guy has. Would a compression test tell anything ....
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| Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2006-10-27 136368
To do in the field would be like brush-hogging or mowing under load for a few hours. It would need to be kept at full load. If you are not loosing oil and you have it coming out the breather then it must be being replaced by fuel oil or antifreeze from a head gasket. Do check the engine temp with a gauge or a hand held laser guided heat detector. There is a unit that would drop in the radiator openning that is economical to buy but use caution removing the cap from a hot engine. ....
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