52 farmall cub venting gas

when i got the cub in the spring i never smelled gas in closed garage i keep it . even in summer . now in winter i smell what i
think is gas when i go in, i put the cap on with plastic on to seal off cap vent. still smells, i do have main seal leak so oil
is on floor, i always turn gas off at bowl. im thinking the main seal oil on the floor is the source of the gas smell???. anyone
else have oil that mells a lot like gasoline. ps i can see the entire undeside of the gas tank and see no sign of gas leaks
anywhere. thanks in advance

If there has been gas in the oil and nobody changed the oil it could make the gas smell you notice. Try smelling the oil dip your finger in it then smell the oil. It will tell you if it is the oil leaking main. IF it is leaving a spot more than a mark it should get changed out with a new seal.

All gasoline engine engine oil smells like gasoline to some degree. It is not necessarily an indication of a problem.

On an old Cub, it would have gotten there via blowby around the piston rings during combustion.

There is no path for raw gasoline to flow from the tank into the crankcase of the engine without creating a VERY large mess in the process. It would have to fill up the carburetor and the intake manifold, then run into a cylinder where an intake valve is open, but for that to happen, the air cleaner connection would have to be perfectly airtight (they almost never are), and the drain in the carburetor would have to be plugged tight (sometimes but not usually). You would notice IMMEDIATELY because your tractor would instantly hydro-lock with gasoline the next time you tried to start it.

Or if it did turn over and Fire just once it would BLOW the oil pan clean off . This happened to a brand new Ford Thunderbird with a new just out 460 on a car carrier at the one dealership i worked for . They had just started putting cars out over top the cab of the truck and the ft ends of the cars were down hill . New line up of cars were just hitting the dealers and this dealer was getting five six loads a day coming in full load . The driver had unloaded all the rest of the cars with the T bird last and went to start the car and it acted like a dead batery , This did happen a lot more then ya think with new cars due to a glove box falling open in transit or and interior light left on or other lights on . So the LOT DOG gets the lots NEW BRONCO with the STARTALL that is 6-12-24 volt and pulls up ext to the truck and hands up the jumper cables to the driver to hook up to the group 27 battery , the lot dog fires up the start all and they give it a try on 12 and it does not want to turn over so lot dog flips iot to 24 volt and the driver turns the key and KER BOOM the car explodes into a huge ball of flames oil pan opens up a mix of oil and gas go everywhere in flames the lot dog takes off Jessy Owen style the driver jumps to the ground in a dead run the Bronco is no onfire the semi is on fire the T bird is on fire and everybody is grabbing every fire extinguisher and emptying them and nothing is helping By the time the fire dept gets there the fuel tanks on the truck explode sending maybe 15o gallon of gas ( yes the truck was and again say was a 534 GAS ) . And something like ten brand new cars now toast. I have aslo heard of tractors that have filled the oil pans but still turned over and go BOOM in the barn .

looks like ill have to pay attention to better cleanup or fix the rear seal.i have only maybe couple hrs run time on the oil but its been in there since last april.

Possible fuel leaking by through carburetor, evaporating

(quoted from post at 10:58:54 01/10/23) i always turn gas off at bowl

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Fuel can still leaking by a shut sediment bowl. A lot of these do not seal 100%. A small amount will evaporate before showing a leak on the floor.

the packing nut on the sediment shut-off valve maybe needs to be
tightened just a tad