Small Engines (Lawn Mowers, etc.): Lawn Mower Engines Revs faster after oil change, briggs stratton, lawn mower engines

Question
Hi Michael,

I have a Murray 22" 3.5 HP "basic" lawn mower with a Briggs & Stratton (B&S) engine, which I purchased new from Wal Mart in 2001 for $100.  I use it to compliment my riding mower.  I just changed the oil and gave it a general cleaning, without adjusting anything.  Now, the engine appears to rev twice as fast as it did before the oil change!  I used B&S 10W-30 oil for mowers and tractors.  It is cutting fine, but seems to be reving much too fast.  It even releases a little smoke from the heat when cooling down.  I have never had this happen before.  Any suggestions to avoid carting it to a repairman?

Many thanks,
Chuck  

Answer
Hi Chuck,

I would use a straight 30 weight for outside temps of 30 degrees and above and not 10W-30 which is really a 10 weight and for cold weather.  The smoke is a sign of too much heat.  I'm surprised that the engine would rev that much higher though and there may be another problem.  But try the oil change first.

Let me know how you make out.
Michael