My rider is 20 years old and has never given me trouble. I just do the yearly maintenance on it. Mowed twice already, but today when I got out there it started blowing blue/white smoke, which dissipated when I stopped moving. Looks like it is coming from the muffler, and there was a couple drops of oil on top of the rocker cover. Could it just be the rocker cover gasket dropping oil on the muffler? Everything I have read so far says on this topic suggest it is probably the head gasket. I have yet to see one on the rocker cover gasket. Has anyone ever had this happen?
B&S model 311707 in my Craftsman riding mower blowing smoke
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charleneje
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try taking the dipstick out of the engine when its running and if it is blowing air and spatters of oil out of there the head gasket is blown I know because I have two mowers with B&S engines both have blown the head gasket and one of them keep on blowing the head gasket same thing everytime smoking running kind of rough and air pumping out of the dipstick tube.
Yep, spittin' out oil. Guess it is the head gasket then. Did you change them yourself?
Thanks for the info.
bertsmobile1
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Almost every vertical shaft engine will do this blown head gasket or not.
One of the tests is to run the engine then turn it off, count to 10 and remove the dip stick
If the gasket is blown internally you with get little wafts of grey-white smoke coming out of the dip stick tube.
Another symptom is a sudden roughness , even backfire & some blue - grey smoke from the muffler when a load is applied to the engine like engaging the blades.
Yet another is a rough stop, again usually with a lean burn backfire when the mower is turned off
Yet another is heavy puffing out of the breather tube usually associated with oil dampening of the air filter, but an over full crankcase can also exhibit this same symptom .
mitchstein443
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If you put too much oil in the crankcase it will do what yours is doing. Bluish greyish smoke coming out of the muffler is an idication of nothing except the motor is burning oil in the combustion chamber.
Possile causes include, thin oil(old or wrong type), worn piston rings, worn cylinder wall, worn valve guides, sticky valves, blown head gasket, engine was tipped (from the normal upright position) and most common, too much oil put in the crankcase after an oil change or just added.
If oil is dripping from the valve cover onto the muffler then there is an oil leak, most likely the valve cover is leaking, it will burn off he muffler as blueish greyish smoke BUT will not burn more or less when under heavy load like it will if it is getting in the combustion chamber.
I never heard of oil causing backfiring in any engine ever from a chevy 350 down to a B&S single piston, back firing in a B&S at shutoff is pretty common, it usaully means the fuel shutoff valve on the carb is not engaging properly or was removed. Many people remove the shutoff when they go bad and refuse to let fuel into the carb at all, I prefer ot to do that because if it is present and the person stores the mower ovr the winter without drining or manually shutting of the gas the tank and it is gravity fed then the carb will continue to allow fuel into the bowl as it evporats and speeds up the eventul gunking up of carb.
hope this helps someone out..
Possile causes include, thin oil(old or wrong type), worn piston rings, worn cylinder wall, worn valve guides, sticky valves, blown head gasket, engine was tipped (from the normal upright position) and most common, too much oil put in the crankcase after an oil change or just added.
If oil is dripping from the valve cover onto the muffler then there is an oil leak, most likely the valve cover is leaking, it will burn off he muffler as blueish greyish smoke BUT will not burn more or less when under heavy load like it will if it is getting in the combustion chamber.
I never heard of oil causing backfiring in any engine ever from a chevy 350 down to a B&S single piston, back firing in a B&S at shutoff is pretty common, it usaully means the fuel shutoff valve on the carb is not engaging properly or was removed. Many people remove the shutoff when they go bad and refuse to let fuel into the carb at all, I prefer ot to do that because if it is present and the person stores the mower ovr the winter without drining or manually shutting of the gas the tank and it is gravity fed then the carb will continue to allow fuel into the bowl as it evporats and speeds up the eventul gunking up of carb.
hope this helps someone out..
mitchstein443
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Oh, also, oil splashing around in the crankcase even spewing out of the dipstick is pretty common as the crakshaft slas into the oil and throws it all over the insides.
To tell if compression is leaking into the crankcase (blown head gasket, worn cylinder walls worn valve guides etc etc) put your finger over the dipstick hole (or palm) you should not feel it trying to push your hand off, you should feel a slight vacuum. And bluish smoke slowly coming out of the dipstick is normal once the engine warms up. it gets hot inside there nd oil will smoke a high temp. but it shouldn't pour out like an muffler..
Harbor freight has a neat tool called a compression tester, ebay amazon sell them also. great tool to take the guess work out of these issues.. they are cheap and last a very long time (mine is over 20 years old and still works). they are same for cars as well as mower engines. Loss of compression again shows a leak, maybe head gasket, cylinder alls, valve guides etc etc..
To tell if compression is leaking into the crankcase (blown head gasket, worn cylinder walls worn valve guides etc etc) put your finger over the dipstick hole (or palm) you should not feel it trying to push your hand off, you should feel a slight vacuum. And bluish smoke slowly coming out of the dipstick is normal once the engine warms up. it gets hot inside there nd oil will smoke a high temp. but it shouldn't pour out like an muffler..
Harbor freight has a neat tool called a compression tester, ebay amazon sell them also. great tool to take the guess work out of these issues.. they are cheap and last a very long time (mine is over 20 years old and still works). they are same for cars as well as mower engines. Loss of compression again shows a leak, maybe head gasket, cylinder alls, valve guides etc etc..
reynoldston
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Let's start with what model is your Briggs?
Reynoldston, haven’t seen you around in years,, but glad to see you back. Hope everything is going well for you and yours and am looking for more of your aged wisdom.