I have a Suzuki LT160 that is surging. Its RPM changes from almost stalling to a very fast idle. I have changed the plug, cleaned the air filter, drained and flushed the gas tank and completely dissassembled the carburator and used carb cleaner on all the ports/jets and passages with the same results. I'm still thinking I've missed something in the carb. Any ideas? The old plug was black, indicating a rich condition.

 

try an air leakin the intake

 

Thanks! I'll double check that in the morning since I did have it off.