Author Topic: 11HP Briggs and Straton pumping oil out of breather  (Read 6717 times)

barry100

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11HP Briggs and Straton pumping oil out of breather
« on: August 20, 2009, 04:59:05 AM »
Hi All
Ok so its not a lister ( but it is air cooled), I bought  a Lincoln genset welder powered by a 11 HP B and Straton engine, it started second pull ran well not a wiff of smoke, then after about .5 an hour of welding  it pumped about .25  litre of oil out of the breather in about 2 minutes then stoped pumping the oil out and ran well again , the engine has a little crank case compression but in my opinion  not enough to pump all that oil out so fast, the inside of the air filter box and the paper air cleaner were clean and dry before it happened not after though, when I stopped the engine the oil was on the low mark, also the spark plug was also clean.
any ideas
Barry

Tom

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #1 on: August 20, 2009, 05:08:55 AM »
Usually this is caused by blowby due to worn rings or scored cylinder. If this engine had sat for a while, and the oil had not been changed some moisture in the oil may have flashed off to steam and blown the oil out. How does the remaining oil look?
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

compig

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #2 on: August 20, 2009, 10:38:16 AM »
If it's not run for a while the rings could be a bit sticky , it may settle down after some run time. Change the oil and see how it goes for a while.
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mobile_bob

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #3 on: August 20, 2009, 03:54:38 PM »
does the crankcase breather pipe/tube go back into the intake between the airfilter and the carb?

if so, all it takes is a filter that is starting to get plugged to vacuum out all  your crankcase oil.

this was an attempt at early epa compliance, and killed many enigne's

i had a small genset that died in 5 hours due to this bit of poor engineering forsight.

if yours is one of those, just remove the tube from the intake, and of course plug off the hole in the intake
and leave the pipe/tube exposed to the air, or
if you are a purist/green kind of guy, reconnect it to the aircleaner on the opposite side of the engine
where there is no vacuum.

bob g
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(useful forums), utterpower.com for all sorts of diy info

panaceabeachbum

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #4 on: August 22, 2009, 04:37:46 AM »
the crankcase scavenging tube was what I was thinking also.  If its new and not a blow by issue, maybe you just overfilled the cranckcase with oil

mobile_bob

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #5 on: August 22, 2009, 04:50:47 AM »
i was really upset to lose a new genset engine at only 5 hours due to the oil being sucked out of the crankcase
with this poorly thought out or rather epa afterthought crankcase breather pipe recirculating scheme.

all they had to do was move it to the atmosphere side of the filter and all would have been fine, probably didn't do that
because the oil vapor would accelerate dust clogging the foam airfilter or something.

i never even thought to look before putting it into service, sure sucked dropping the whole unit in the dumpster after
5 friggin hours.

i had expected around 200 trouble free hours at least, it was only to be used very infrequently on my service truck to provide
power for a skilsaw, sawzall and angle grinder.

funny how fast they seize up, and how things seem like slow motion when it first sounds like something bad is happening,, you can't get from the other end of a 25ft ext cord in time to shut it down before the damage is done.

if i ever get another one, which i have no need for now, i would simply remove the tube and let it hang like the engine's did for a 100
years before the epa,, and let it pollute its little ass off.

at least it will last long enough to be useful.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

barry100

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #6 on: August 22, 2009, 09:40:39 AM »
Hi All --Thanks for your replys, as soon as the oil started to be pumped out I removed the breather pipe from the filter housing, but it just kept on pumping out,not sucked out untill it got to minimum oil level then ran good no smoke and a little crank case pressure, I thought it might have had petrol in the oil and that was causing the pressure, so next day I topped the oil  up again, same thing happed till the oil level dropped, the only thing I can think of now is the oil throthing up as multigrades can do
Barry

Wizard

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #7 on: August 22, 2009, 09:29:57 PM »
Try straight 30 or 40 if weather is really hot.  Have to be non-deragent oil like lister requires to let junk fall to the sump.

Cheers, Wizard

compig

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #8 on: August 22, 2009, 10:21:16 PM »
How are you checking the oil level ?
DON'T STEAL , THE GOVERNMENT DOESN'T LIKE COMPETITION !!!
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Wizard

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Re: 11HP Briggs and Straton pumping oil out of breather
« Reply #9 on: August 22, 2009, 10:54:37 PM »
On those, usually the dipstick if you cannot see the oil level, and for ones that has specific design that you can see oil level visiually with tunnel leading to the sump, fill to the roof of the "tunnel".  That all depends on models of B & S.  Consult the manual.  Again, straight oil only.

Cheers, Wizard