Small Engines (Lawn Mowers, etc.): Toro mower engine (old GTS 5) with mikuni carb, mikuni carb, fuel stabilizer

Question
The mower was unused for 2 years, properly stored, and when I attempted to start the engine, it would not start.  I disassembled the carb and cleaned it, running carb cleaner though all the passages I could find, removed and cleaned the jets, etc...  At this point the engine started, but ran roughly.  I got it adjusted to a point where it would run with the choke fully open , but it had little or no power, engaging the mower blade cause it to stall.  By closing the choke about half way the engine runs with good power, engages the blade, etc...  but is it not right...  I assume the engine is running lean, but I am not sure what to adjust, clean.  Any help would be appreciated.  I believe this is a Toro model 20526C.

Thanks,

Arnie


Answer
The carb seems to be not supplying the right amount of fuel, a passage way is still blocked with gummy varnish. The only way a mower engine can be properly store is with fuel stabilizer, but even fuel stabilizer is only good for about 18 months. Draining the fuel and running it empty is not enough fuel still remains in the jets and bowl. I can't tell you what circuit is blocked other than the main jet circuit. Each carb is different. Some passages aren't even accessible, thats why us shops spend thousands of dollars on ultrasonic parts cleaner machines. Only thing I can suggest is to go to your local Autozone store and buy a  gallon of the carb parts cleaning solution that has a basket that comes with it and soak that carb over night. There are passages that are hard to see, even the float bowl cover has some holes sometimes,a small piece of wire is needed to free the holes sometimes, BUT do not EVER force a wire too big into the holes it will destroy the carb.......Tom