Does yours have the Briggs w/ the auto choke? Or which engine does it have?

Running rich. We would have to know the engine make/type.

does this help...off the cowl covering the engine...Toro GTS 6.0 99-6013...

As far as auto chocke...there is no chocke that I set...just push the primer 3X and pull the string.

thoughts

I'm not sure what good gas is.
How old is the gasoline that you are using? If it is from last season I would switch to new gas whether you stored it with Stabil or not. Some gas cans can allow a good amount of evaporation. Are you trying to start using old gasoline in the tank?

If the gasoline is new I would suspect that the primer bulb isn't working.

ok, Engine run dry last year beofre being stored in shed for winter. New treated gas this year. Popped filter off, hit primer button...see gas dripping down....other ideas...thoughts...

Also, again, the plug fouled out after half a season Last year and the mower was used infrequently...pop's snapper has the same plug in it for 3 years now is used much more than mine...starts right up....

Gas should not be dripping down anywhere. If it is from the primer bulb or the carb you need to have it rebuilt. That may solve your problem.

Has the oil been changed and checked? Is it overfilled?

I assume that's the Briggs 12H802-1776-B1 engine?

My theory is the needle & seat in the carb is leaking.
This allows gasoline to enter the crankcase and dilute the oil, which is BAAAAD!

Smell the oil for the presence of gasoline.

Anyway, the thinned out oil gets past the piston rings very easily and is burned in the combustion chamber.
SMOKE!

re:
Gas should not be dripping down anywhere. If it is from the primer bulb or the carb you need to have it rebuilt. That may solve your problem.

The toro dealer told me to remove the filter and look in there for a little hole. They said I should see gas shooting thru the hole when I hit the primer bulb. I do.

Re:
My theory is the needle & seat in the carb is leaking.
This allows gasoline to enter the crankcase and dilute the oil, which is BAAAAD!

I don't smell any gas but it could just be my nose. If this is the problem, has it caused permanant damage? How hard is it to get to the carb. I have repalced the needle, seat etc on my snowblower....is this a homeowner job?

To be honest I think you should take your mower in for a complete service. Your post is a bit hard to follow but it sounds like you are going to start replacing parts. A better idea would be to have a knowlegable technician look it over.

"Each year I buy a little kit containing the oil, filter and plug and change all 3."

Did you change the oil before you tried starting it this year?

Replacing the needle & seat is a pretty generic task. IF you've done it before.....
You just might have to remove some stuff to get to the carb.

You haven't confirmed which engine you have, so at this point I'm still guessing. That means I'm guessing at potential problems/solutions.

Spark plug in a well-maintained mower can last for 15 years. Yours is running rich and/or the oil is contaminated as explained above. Engine won't last long like that.

Bill is probably correct on the engine - but it would be good to know. There are still too many variables. The number is likely stamped above the cylinder head or on the tin above the muffler guard in the shroud of the engine. Back to the fuel. You should consistently use a stabilizer that has the ethenol protection. No exceptions. Don't bother running it dry either for storage. Adding treated fuel to a system that, well- may have had plain stabilizer does little also. If there is not fuel currently overflowing from the carb and the engine run quality seems good- then your once fuel leak when putting a "dry carb" into service is most likely a non issue.

I ALWAYS use a non-ethanol gasoline in both my motorcycle and lawnmowers (IE: Union76,conocophilips,some independents, etc.) It costs a little more but your plastic parts will last longer.