QuestionI have a Briggs and Stratton push mower (3.5 HP I believe) that runs at full throttle after starting. It starts with no problem but never does seem to throttle back to normal operating speed. I'm afraid the engine will blow if I run it for more than a minute or two. Last year towards the end of the mowing season, it started cycling between full throttle and low throttle; cycling every 4-5 seconds. Now it is all full throttle and doesn't slow down. Any ideas?
AnswerHello Drew:
>>From your Description it Sounds like the Carburetor Requires Soaking and Cleaning.
>>The Surging at the End of last Year is an Indicator that Varnish has Built up to the Point it was Restricting the Gas Flow through the Jet.
>>I Suspect that you can bring the Throttle Back under Control by Spraying the Throttle Thru Shaft with Spray Lubrication and Moving the Throttle by had to Free up the Throttle Thru Shaft.
>>Small Engine have the Carburetor Full Open when the Engine is Not Running. The Governor Pulls the Carburetor Closed when the Engine Starts.
>>If the Throttle Thru Plate is Not the Cause, then
>>The Governor May Require Setting. If So, then
>>The Following is an Instruction File I Made for Setting the Governor Arm Correctly. Any Input is Appreciated.
>>If you Removed/Loosened the Governor Arm from the Governor Shaft or Put the Linkage in a Bind when the Carburetor was Removed, then Reset the Governor.
>>**To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops.
>>Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt.
>>If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm.
>>**If it Still Runs at Full Throttle, then Check the Internal Governor.**
>>If you Require Further Assistance, then
>>>>Send me the Model and Type or Spec Numbers Off the Unit, Please. With these I can Locate the Proper Manual and Better Assist you. The Model Numbers May be Stamped Into the Blower Housing (metal engine cover) Above the Spark Plug. Many horizontal shaft, overhead valve engines have these numbers stamped into the OHV rocker cover. However, on certain overhead valve powered generators, the equipment manufacturer installs a decorative chrome rocker cover OVER the Briggs cover. If your engine has a decorative cover, it may be necessary to remove it in order to locate the Model, Type, and Code. If this is a Briggs and Stratton Engine, then you can Also Use this Site Addy; http://www.briggsandstratton.com/maint_repair/BS_modeltypecode.pdf for Assistance in Locating the Model, Type and Code Numbers of the Engine.
>>Please, Do Not Hesitate, If you Hit a Snag, if I Missed Something or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.
Good Luck
Respectfully
John
>>PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
