Small Engines (Lawn Mowers, etc.): 4 hp Tucumsa engine speed variation, ariens snow blower, speed variation

Question
Hi;

I just picked up a Ariens snow blower from the curb the other day and noticed that the gas system was sedimented out all through the tank and carb.  I cleaned the tank and filter, took apart the carb and cleaned it out well.  It started on the first pull but I couldn't get the rpm's up or the engine to stop oscillating.  (that spring loaded lever that controls an internal butterfly in the carb? was tied in with the problem, oscillating back and forth.  When I held it open? rpm's went way up and the oscillation stopped.  What does that thing do and how do I fix the problem?

Thanks,
Scott Usher

Answer
Hi Scott,

The ocillating, also known as the carb is "hunting",  usually is caused by a weak, damaged or incorrect governor spring.  The spring, on the carb linkage, allows the throttle to work with the governor so that full power can be automatically applied as the snowblower needs it when under a full load.  Most all engines have this. You will need to replace the spring with a new one.  You can get one from a power equipment shop.  Bring the engine make and model # if you can get it off the engine cover.  Bring the old one in case it happens to be the original one and can be matched up.

Let me know how you make out.

Good Luck,
Michael