# briggs oil leaking from breather tube



## bonzo

Hello everybody. I have been working on this one its a sears craftsman snow blower. model 536.881501 with a Briggs and Stratton model 09A413 type 0202E1. I got it running and now it is leaking oil out of the breather hose. Anybody have any ideas on this one? Thanks


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## 30yearTech

Make sure the engine crankcase is not over full with oil. If that checks out, have a look at the breather assembly, and make sure there are no air leaks into the crankcase.


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## Sir Thomas

bonzo said:


> Hello everybody. I have been working on this one its a sears craftsman snowblower. model 536.881501 with a briggs and Stratton model 09A413 type 0202E1. I got it running and now it is leaking oil out of the breather hose. Anybody have any ideas on this one? thanks


It's always good to mention how old the machine is. As you know the breather hose is connect to the valve chamber where the valve spring is. If, the crankcase is not overfilled as 30yearTech mentions then take the breather cover off (I've never run one without it) and run the motor. Check and see if there is oil coming out at the bottom where the valve shaft goes into the crackcase. If oil is coming out liberally, there may be a worn valve retainer. I've worked on an old 5 horse Briggs and Stratton but never had to take the valves out so I don't know what kind of seal is supposed to be around the valve retainer.


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## 30yearTech

L head Briggs engines don't have seals on the valves. There is also no pressure on the oil supply to this engine, so oil will not leak from the valves.


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## Rentahusband

I have never run an engine without the valve cover, I think it would be a bit messy. Isn't there a little crankcase pressure built up to supply a little oil to lubricate the valve stems/lifters? If the oil is not overfull you may have an issue with blowby of the piston rings. I had an issue with a Kohler engine spitting oil out the breather tube. It was a newer engine and I could not figure out why it was doing this. I had the head off and noticed a fine line of oil on the cylinder wall when the piston traveled down. The cylinder walls were perfect so it had to be due to the end gaps of the piston rings lined up causing combustion gases to enter the crankcase, building up pressure forcing oil out the breather tube. Oil no longer comes out, so the rings must have shifted.


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## OptsyEagle

What about a leak with the inlet valve on the carburetor? 

The theory being that during storage ,gas leaks by the inlet valve, flowing into the combustion chamber and down into the oil. As the motor is used the high temperature in the crankcase causes this oil and gas mix to evaporate and those expanding gases create the pressure required to squeeze it out the breather tube.

Now if this was the case, I would imagine the motor would take quite a few extra cranks to start, so if it is starting fine and quickly, then I suppose the OP could disregard my theory.


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## 30yearTech

OptsyEagle said:


> Now if this was the case, I would imagine the motor would take quite a few extra cranks to start, so if it is starting fine and quickly, then I suppose the OP could disregard my theory.


This is certainly a possibility, that is why I suggested checking the oil level.

If overfull due to gas in crankcase, the engine may or may not start alright, but shortly after starting oil will start blowing out through the crankcase vent due to the oil level in the engine not allowing the chamber to drain. If the breather is vented back into the air filter, it will usually cause the engine to start smoking, choke down and die.


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