Small Engines (Lawn Mowers, etc.): B&S 3.5 HP lawnmower, mail order, governer

Question
Hi

First of all thanks for your time, my question is i have a B&S 3.5HP 9 years old lawnmower, it starts just fine but when its running the revolutions suddenly go up and then down it does that the whole time, ive narrowed the problem to the speed airflow flap i think, that is attached to a spring, is there a way to eliminate that flap? or how do i adjust it? ive looked everywhere for a similar spring and where i live i havent found one. Or what could be causing that king of behaviour?

Thanks in advance

Luis

Answer
Hi Luis,

The flap is part of the governer, which controls the speed.  It is necessary.  When carb "hunting" occurs, a weak spring is usually the cause.  You need a new spring from a repair shop or mail order.  Using the exact same replacement is critical.

Good Luck,
Michael