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Small Engines (Lawn Mowers, etc.)/Pressure washer carb leaking oil



I have a B&S 6hp engine on a craftsman pressure washer, model 580.752300.  I bought it used and it had old gas in it.  Ran fine but leaks oil from the air filter.   Oil level is fine.  I changed the oil.  I hear the float could be stuck.  Wouldn't be surprised but not sure how that causes oil leaks.  Anyway, I want to attempt to clean the float.  I've worked on a holley 600 before but not a small engine carb.  The air cleaner housing blocks access to the bowl.  I assume I remove that and then the bowl.  Anything I should be aware of when disassembling these parts.  Will the float be adjusted after reinstalling?  
Engine info:  family: 1BSXS.1901VF       275228
Engine starts fine when cold but has trouble starting when hot which leads me to believe its flooded

Thank you

ANSWER: Those are carbs are really simple.  However, make sure pay attention to the carburetor connecting links/rods/springs.  I take a picture before removing the carb.

The oil you see may be coming from the valve breather.  Take a look at the link below to locate the Briggs engine model:

Send me the Briggs engine model so I can look up your engine.

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QUESTION: Thanks Eric
I think it's:
120802-0120-D1 03072256

ANSWER: The oil in the carb or air filter may be coming from the valve breather.  Too much Oil can get in the breather either by too much engine tilt, over filled with oil or the wrong weight oil.  There are two drain holes in the bottom of the breather to allow oil to drain back in to the engine crank case.  Oil can get into the air filter/carb through a tube that connects the breather to the air filter base.  You can clean the breather by removing the muffler and then the breather.  Clean with carb cleaner.  While the breather is off clean the tube as well with carb cleaner.  You are just trying to get any excess oil out of the breather tube.

Here is a video on carb cleaning:

I use a pick to remove the inlet needle seat or another (safer) method to remove is to just put some 30 weight oil in the carb fuel nipple and then use an air compressor to blow out the old seat.  The oil acts as a hydrolic pusher to blow the seat out of the carb.

When installing the new seat I spray the new one and the carb inlet needle housing with some WD-40 making it easier to install.

The float is not adjustable.  When the seat is installed correctly the float should be approximatly horizontal or level when you hold the carb upside down.


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QUESTION: I removed the breather and there was a lot of oil on it, its gasket and on the tube to the air filter.  The hole at the top, behind the breather...looks like where the metal tube connects.  Can you confirm?  Spray carb cleaner in there and spray the breather, correct?  Any reason to replace the breather?
Thank you

All sounds correct.  You can replace the breather but I would try cleaning first...we rarely replace breathers.  I'm betting the engine was just tilted too much and too much oil got in the breather and cound not drain out the of the bottom 2 breather holes fast enough before the engine was started.


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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