Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I started up my 11.5hp Tecumseh powered Ariens and it was surging.  Never did that before.  I'm not sure what causes an engine to surge/hunt but here what I did so far in an attempt to correct it.  I changed the spark plug, took off and cleaned the carb bowl and needle and float assembly.  Cleaned the jets with carb cleaner and ran a fine wire through every hole...even the tiny one.  It still surges.   Any ideas on what else I should try...or re-try.  

If it  helps the engine is the OHV variety.

paul 7! everyone above has good advice,i would particularily pay attention to the orifices in the brass nut that holds the float bowl on.use a small wire to wiggle through the holes to make sure they are clean.if there is a high speed needle jet in the center of the brass nut you should be able to cure your surging by going a tad counterclockwise(richer).when it starts if you have to keep the choke on for a long to keep it running you are lean. check all gaskets from carb to intake, and intake to engine.carb clean with jets adjusted correctly,float height set,  no breathing leaks,and good fresh gas, engine should run without surging.i would also dump a good shot of carb cleaner in the fuel.