Small Engines (Lawn Mowers, etc.): Bolens 4.5 revs too high, engine gasket, lean condition

Question
I have a Bolens push mower w/a B&S 4.5 engine.  It is about three months old - it has clean fuel, good oil, new plug - runs well.  but, the other day - I went to start it - and it revved way too high - wide open from the pull.  I checked the carb - good, springs - not broken or worn.  Can't figure out why it runs as high as it does. There isn't a throttle lever - just one speed - so is there anything i can do?

Answer
Hi Ryan,

I'm not familiar with a carb that has no throttle.  Look into the carb's intake and look for a throttle plate.   If there is one, does it move? Is it stuck?  Next, check the carb for looseness.  An air leak at the carb-to-engine gasket would cause a lean condition and over revving.

Let me know what you find.
Michael