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oil in carb

9K views 12 replies 10 participants last post by  DTLMG 
#1 ·
Has anyone ever had this problem. I have a Briggs and Stratton OHV 15 Hp that runs great except under a load PTO engauged and driving oil comes from breather hose to airbox and runs back into carb and causes it to smoke under load. Not sure why it does this?
 
#6 ·
The first thing that I would check is the breather,a blown headgasket won't cause excess crankcase pressure,worn rings would but the breathers job is to stop the oil and only allow crankcase emissions to get to the carb to be reburned.If it's only smoking under load,it's a good possibility that the rings and or cylinder are getting some wear,if it's not smoking to a point of killing bugs or using a lot of oil,it should go for a while yet.
 
#11 ·
If enough oil is coming through the breath tube it can oil soak your air filter and that doesn't help the motor to get enough air. Try washing out the breather and check oil level. then see what happens, maybe a simple fix.

I`ve had people push their mower over to me asking me I hit something and I changed the blade and now it wont start. first thing I look at is the air filter and it`s oil soaked, I remove the air filter and it starts right up. I tell them they tipped it over the wrong way, that is why its oil soaked.:fing20:
 
#12 ·
Id check the head gasket. Pull the valve cover off put the cylinder on copression stroke and put 100 psi to it and look for a leak. You are going to have to find a way to hold or keep the crank from moving. A cylinder leak tester is what I use. a old spark plug with a air fitting welded to it will work..
 
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