I have been running my Stihl chainsaw and what ever 2 stroke I have for 30 odd yrs on those little 6oz bottles from any where. Hardly buy the same brand twice. I add them to 2 gallons of gas. a rich 32:1. Never any fuel troubles. The Stihl specs 40:1 and other than a little smoke while running choked its OK. So far, no complaints from my 50: 1 Husqy weed wacker either. The new stuff is ashless, you gotta mix it purty strong to carbon up stuff.

Okay, let's see; 89 octane fuel is okay. We need to know exactly what oil you put in and how many ounces. Seafoam is okay and 1 oz/gal is not excessive. A 2-cycle will smoke from the exhaust if there's too much oil in the gas. The 10550 has the 'Duraforce' engine that requires a 32:1 mix of Lawn-Boy oil. That's one 8 oz can to two gallons of fuel. Re-reading your post it sounds like you picked up two small bottles of 2-cycle oil, probably a synthetic or synthetic blend, possibly designed for a 50:1 mix. This actually should have been okay IF the mix was properly agitated before putting in the mower. The procedure on these hard-to-mix oils is to add the first bottle to about half a gallon of gas and try to mix it the best you can without slinging gas around. Then add about another half gallon, pour in the second bottle and mix again. Finish filling the can, cap it and shake vigorously. Shake the can before fueling the mower, every time. If I had to guess, I'd say you possibly did not have the oil well-mixed, and the gas you put in the mower was too light on oil. This caused the engine to overheat, usually causing permanent damage. At least it didn't seize, which is a hopeful sign. All Lawn-Boy two-cycles have iron cylinder sleeves, so perhaps it's not too bad. Check the air filter - remove it, wash it, dry it and oil it with 2-cycle oil or special filter oil. I'm trying to figure how smoke could come out of the carb. If you did scratch up the piston and bore, the compression would be low, possibly explaining the poor performance after the incident. This one thing probably explains the constantly-dwindling sales of the 2-cycle mowers leading up to Toro finally pulling the plug - all it takes is one time 'straight-gassing' a 2-cycle and it's junk. If they had been a hot seller, they would have found a way to make them compliant with emmissions laws. As it was, they decided to just get out of that game since the LB share of the market was so small. People today will not pay attention to details like this - they expect everything they use to be a 'refrigerator' - you plug it in and forget it. 4-cycle mowers are easy to maintain and have similar maintenance requirements as cars vis a vis oil changes and air filters.

Sorry I didn't get back earlier on this. Much appreciation to everyone. I was able to free it up and it seems to be working the same as always. I just used a penetrating oil as suggested, tapping the cylinder lightly with a wooden dowel every day. It freed up in about a week.

Beat it like an overloaded donkey! Seriously, pick up the back of the mower and drop it from 6" height. That has been known to free up the float/needle/seat and let it shut off the fuel. Go to a hardware store and get an inline fuel valve and install it on the fuel line. Turn the valve off after use. Start using 1 oz. Marvel Mystery Oil to each gallon of 2-cycle mix, in addition to the regular oil. Chances are your exhaust ports look like new after all that fuel being shot through them.