8 hp tecumsch engine for snow blower oil comes out the side vent tube when running

Check the bushings, O-ring, seals, and gasket if your snow blower is leaking oil. ... Oil seals are located around the input and output shafts of the crankshaft, and stop oil from leaking out. Their failure can cause a mess and could also cause engine damage if enough oil leaks out.

There should be a plainly marked filler tube with a cap and indicator of how much oil is in the engine attached to it. you pour oil down that tube to fill it.

you need to remove carb for cleaning... if it has an adjustment on the bottom of carb try turning it SLOWLY in and out... also possibly a screw on the side under a black cap... might try it as well engine model number would help here

its over filled or vent is plugged

If you can remove the bowl without removing the carb from the engine, take it off and clean it well in some fresh gas with a toothbrush. Then, get a can of carburetor cleaner and spray it up into the small tube under the carburetor and through any small holes in the tube either on the sides or the bolt that holds the bowl on, or both. It should then run on new FRESH gas. If you have gas older than a month, put it in your car and get fresh gas for the blower

What engine do you have? Tecumseh those are usual 18-21oz Not sure with briggs, but will be around a 1/2 qt (16oz) start there. Add a little at a time to bring level up. get back if you have and need more specifics.

Your question as I received it did not specify the engine make, but most 8 hp Techumseh, B&S and Powermore engines take 22 to 32 oz of oil. Buy a quart, put two-thirds of the quart in the engine and check the level with the dipstick or fill hole. Add more if needed to come up to the "full" mark.
All the manufactures and Craftsman recommends 5W30 for 4 cycle winter use.
You can use regular sae oil, but I prefer to use Mobil ONE or a heavy duty oil because air cooled engines run hotter than car engines. Look for a SC/SD or greater rating on the bottle.
Change your oil once a year.
Feel free to as any other questions about your snow blower. Don't forget to rate this answer!

The oil leak normaly would make the 'friction disc' inside the frame slip so as to not drive the axle.
Locate the oil leak
#1 engine crankshaft seal
#2 engine crankcase cover gasket
#3 engine overfull so that the excess oil is coming out of the crankcase breather tube and running down inside the frame

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

You either have a head gasket going bad or your piston rings are shot which causes air to go down into the crankcase building up pressure which exits through the breather tube.

if this model has a fill tube on it- turn the unit on its side to drain.