# B&S 17.5 hp on riding mower surges



## KenOverton (Nov 30, 2010)

My neighbor bought a used Craftsman riding mower with a B&S 17.5 hp, Model 31C707_3346_G6. The mower was originally bought in 2013 and used one season, then sat until my neighbor bought it yesterday. No fuel stabilizer, so the fuel was bad. Engine would not start unless fuel was injected into the intake, then would start and shut down. Drained the fuel, sprayed Sea Foam into fuel inlet and air intake and the engine would start. Let the Sea Foam sit for a while and put in fresh fuel. Engine started and would run only while choked. After a while was able to open choke but the engine surges at full throttle (governor is cycling). Replaced fuel filter but that didn't seem to help anything. If the engine is put under load (engage mower deck) the surging is less but does not go away. 
Any help would be appreciated.

Ken


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## AVB (Nov 28, 2014)

Carburetor is needing a full cleaning idle and no load passages are still partially clogged. Also the main metering jet o-ring maybe bad if it has the Nikki carburetor.


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