Small Engines (Lawn Mowers, etc.): Erratic speed, cylinder compression, steady speed

Question
Hi John:

My friend is having a problem.  His lawn mower engine won't stay at the same speed.  He changed the oil, new plug, new air filter (at my suggestion), and it still won't hold a steady speed.

I helped him troubleshoot, and the choke springs were worn, so I forced the choke full open.  It runs much better (higher speed), but the speed still fluctuates a great deal.  What do you think?

Sincerely,

Harvey

Answer
 Hello Harvey:

 1- Clean and Rebuild the Carburator. 2- If the Carburator Clean and Rebuild didnt Help, then Check the Compression. If the Cylinder Compression is Low, it will cause the Problem you Described. Hope this Helps. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John