Why is my Troy-bilt Mustang RZT blowing oil out of crankcase breather tube?

Very dangerous unless you live in the middle of nowhere, have no children or pets. Just join the wires together, it is a simple switch. Easy to buy a new one.

Wiring Diagram

https://www.google.com/search?q=troy+bilt+mustang+50rtz+wiring+diagram

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its over filled or vent is plugged

It possible that the PVC is stuck closed or the hose attach form the PVC to intake manifold is either pinch shut or the hose has

collapsed, not allowing the crankcase to have a negitive presurre. The other possiblity is the cylinder rings may have to much blow by thus forcing the oil out throught the dip stick tube. Check the PVC system first.

at least one quart up to 2 quarts

Here's the diagram for that mower, I'm assuming the deck belt broke : http://www.partstree.com/parts/?lc=troy_bilt&mn=17AA5ABP766+RZT+50+%282006%29&dn=769021650003
Belt is 134" x1/2" Troy-Bilt# 954-04044A

Hi and welcome to FixYa, I am Kelly,
I doubt it is a head gasket. First check to make sure the oil level is not over-serviced. Then if the oil level is correct and after 10 minutes it is still smoking you will have to remove the breather assy on the side of the head where the valves are and clean the reeds with solvent. (might require a good soaking) The crankcase is over-pressurizing causing oil blow by via the valve stems. Sometimes you will experience up to 4 minutes of oil smoke if you have tipped the mower in any direction other than flat. If that is what caused your oild smoke episode it will clear and there is nothing you need to do other than let the engine run. If it easily repeats the smoking after running for a bit routine you most likely have a sticking crankcase / valve breather reed. Cleaning it usually will correct the excess smoke problem. You should be able to remove the breather without removing the carb for cleaning.
If you have a head gasket failure the engine simply will not start. Since the engine is an overhead valve design it is possible to have a head gasket fail but..... highly unlikely unless someone has done recent maintenance on the valves and disturbed the head gasket. I have not seen a honda head gasket failure that was not induced by someone doing maintenance on a cylinder head. The design of the head even with minimal bolt tightening torque will allow the engine to run just fine and not ruin the head gasket.
Should you require more information I will need your exact engine model number from the crankcase of your engine just aft of the oil fill tube on the base of the crankcase.
Thanks for choosing FixYa,
Kelly

That sounds like the crankcase breather valve. It should have a rubber hose running from it to the air filter mounting plate. But it should not let oil blow out of it, I would replace the breather and hose and that should take care of the problem. The breather is held in with two screws just remove and replace. There is a very small drain hole in the bottom of the breather housing just make sure it is down so the oil will drain back into the crankcase and not run out.

Frank

Your oil breather (on the side of the engine opposite the carb) may be malfunctioning/defective allowing the carb to **** oil from it. There is a breather tube that crosses over the top of the cylinder connecting the crankcase( oil) breather to the air filter housing. Check the oil level and the condition of the air filter and esp. the oil breather. It serves the same function as a PCV on a car engine.

it could need a oil change if it as some age to it could need a new ring set or a new overhaul and it my need a new plug ...

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.