Briggs & stratton problem

mrfred54

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the motor on my lawnmower is blowing oil out the vacuum fuel pump. anyone know what causes this and what is the fix. this is a 17HP model #31F777
 

motoman

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The pros will respond...Perhaps "blowby" from worn ,broken rings or bore wear. Combustion is not fully captured in the chamber and some is going downstairs where it pressurizes the oil which looks for a way out? (home owner talking).
 

snapsstorer

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another possibility is worn valve guide seats. they be worn enough that you may be getting blowby on them
 

Rivets

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Where are the valve guide seats? I suspect a blown head gasket.
 

EngineMan

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Hmm I was going to say "blown head gasket" to:frown:
 

mrfred54

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the motor on my lawnmower is blowing oil out the vacuum fuel pump. anyone know what causes this and what is the fix. this is a 17HP model #31F777

found the problem..... breather tube was off at carb. must have been off all winter and a spider had a web inside the tube and was plugged . didnt know this when i put it back on the carb. and started mowin this year. when i took crankcase breather apart to look at the check valve and didnt see anything wrong, i look into the breather tube and got lucky to even see the plug web with all kinds of crap stuck to it. run great now and no oil leak
 

EngineMan

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So it wasn't blown head gasket then....! well done good for you.:thumbsup:
 

motoman

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Mr Fred, Good eye and good ending!
 

Ifixdit

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found the problem..... breather tube was off at carb. must have been off all winter and a spider had a web inside the tube and was plugged . didnt know this when i put it back on the carb. and started mowin this year. when i took crankcase breather apart to look at the check valve and didnt see anything wrong, i look into the breather tube and got lucky to even see the plug web with all kinds of crap stuck to it. run great now and no oil leak

I'll have to add that one to my flowchart..."did ya check for spiders in the breather tube?" "Doggone if I haven't seen it happen a dozen times!!" :laughing: Do you know what kind of a spider? Maybe the manufacturers can come up with some sort of OEM repellant :laughing::laughing:
 

ILENGINE

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I'll have to add that one to my flowchart..."did ya check for spiders in the breather tube?" "Doggone if I haven't seen it happen a dozen times!!" :laughing: Do you know what kind of a spider? Maybe the manufacturers can come up with some sort of OEM repellant :laughing::laughing:

The spider repellant is added to the factory installed smoke.
 
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