Small Engines (Lawn Mowers, etc.): Huskee Lawn Mower, vacuum hose, carburetor

Question
Hi,

I have a 139cc Huskee lawn mower that I bought last year, and it ran great. Now it has trouble idling. It runs, but it revs up, then down. Never stalling. It starts on the second or third pull. A friend mentioned a vacuum hose. Any idea what is causing this? Thanks

Kenn

Answer
Your carburetor needs a good rebuild.  You're describing surging which is caused by an inconsistent fuel/air supply.  It could be a leak or it could be something plugged up.  A good rebuild and thorough cleaning should catch most items.  What's the engine make and model?