: : In reading the question concerning leaving the fuel valve on sediment bulb open and discovering gas in the crankcase, I have a dumb question, how does the gas leak into the crankcase?
: : Granted if the float or needle valve don't seal off completely the gas will flood the carburetor. Since most tractor carbs are downdraft it would appear that the carb would have to fill up, then the intake manifold fill up, then perhaps an open intake valve would fill a cylinder, then perhaps the lighter viscosity gas could leak past the rings and seep into the crankcase.
: : Is this what happens or am I missing something?
: OK, so your not a moron, and yes, your right in your description of what can happen. Many carbs though have a porous bronze bleed out drain in the bottom. You haven't been standing on your head a lot have you ? I think you will find that most tractor carbs are "up"-draft except for side drafts like Deere.
: Have a good one. :)
to : Not a moron....
The probelem you ae referring to is not a stupid question, and happens a lot in older farm tractors. The gas is not geting into the crankcase from the carburetor, period. The gas you are getting into the crankcase is unburned fuel from a rich mixture in the combustion chamber, and combustion itself is forcing it down the cylinder walls because the piston rings are very worn. This also happens frequently when the carb is partially obstructed in one of the low speed circuits, and you are forced to run with the choke partially out in order to make the tractor run properly.....ThisIf you are having this problem..first check the condition of carb...then perform a compression test to determine the condition of the engin...apparently quite worn.A new set of sleeves and rings, with possibly a carb overhaul will cure your problems. Do not run tractor with the oil thinned down with gas....if i can be of any further help feel free to email me...good luck