Small Engines (Lawn Mowers, etc.): mower belt routing/engine preformance, electric clutch, faulty valve

Question
I bought a used snapper LT16 it has a two blade 41 '' deck engine is 1985 16hpB&S opposed twin. not sure how to route the belt parts break down shows a twist right below the electric clutch on the front of the engine.?


the engine was smoking and pop ing out right bank and once and a while the left. cleaned valves and seats and piston tops added marvel to gas and oil added lead substitute to fuel changed needle in carb had no point replaced fuel pump diaphram&springs along with the spark plugs runs much better no smoke only pop once and a while seems to be getting better. valves sticking ? also changed the oil three times got real dirty real fast first two times ran it about 3 hours or less. any suggestions would be greatly apriceated. thanks will e fix it ?

Answer
Hi John,

I'm not sure of the exact belt pattern.  Try to follow the path, considering the rotation of each blade, engine and idler pulleys.

As far as the engine popping, I would suspect the valves.  One or more could be sticking or worn and leaking.  A compression test would indicate a faulty valve.

Good Luck,
Michael