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JON, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1080
Experience:  Certified Small Engine Technician
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Briggs vertical shaft 10.5 hp I/C engine, the engine is

Customer Question

Briggs vertical shaft 10.5 hp I/C engine, the engine is blowing back out through the carb. I have replaced the cylinder head gasket, lapped the intake and exhaust valves to make sure the are seated. Set the intake lash at .005 and the exhaust lash at .007. I just pulled it off the mower tonight and dropped the sump thinking I would find a malfunctioning compression release, but nope, its working just fine. Has me stumped
Submitted: 12 months ago.
Category: Small Engine
Expert:  JON replied 12 months ago.

What is the model and type of engine?

Customer: replied 12 months ago.
Model 215802 Type 0115ET
Expert:  JON replied 12 months ago.

May be a dumb question, but what is oil level at?

Expert:  JON replied 12 months ago.

Have you check that the breather passage is clear. May need to replace. This is the biggest issue I have with them blowing back through the carb.

Customer: replied 12 months ago.
48 ounces of oil as specified by Briggs. It is for some reason blowing back out the intake, has briggs had an issue with cam lobes slipping on the splines?
Expert:  JON replied 12 months ago.

possible that the reed is bad and not working properly. This will cause blowback through carb like you are referring to

Customer: replied 12 months ago.
Reed? Are you kidding me? you don't know a four cycle engine from a two cycle engine?
Expert:  JON replied 12 months ago.

crankcase breather. Has a reed inside it. . one way check valve. will allow oil to flow out to carb if it is not working properly

Expert:  JON replied 12 months ago.

can also be caused by a loose oil cap or oil cap not sealing, but RARE!

Expert:  JON replied 12 months ago.

Consist of part numbers:

Briggs and Stratton 697124

Briggs and Stratton 794682

Briggs and Stratton 794683

you also have a gasket and 2 screws included.

If the hose is split or cracked, it can cause this problem you are having.

If the reed is not opening and closing properly, it will cause this problem.

Pull the breather hose, from your intake, and see where the oil comes from.