Question
B&S Governor
Hello John,
I have a rather old Masport 635 mower with B&S 4 stroke motor Model 100708, Type 0129-04, Code 8806 1025. The engine revs are 'hunting'. The governor arm is very free. All seems normal in the spring/linkage. Have you any tips for me?
Thanks
Rod
AnswerHello Rod:
>>You have 1 of the Last of the Best Engines that were Once made by Briggs & Stratton.
>>This Problem can be caused by a Damaged Flywheel Key, Low Compression or a Dirty Carburetor.
>>You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/parts.html and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #10 . Then Select the Folder #100700. **Note: you can Download and Save the Breakdown for your Engine by Selecting the 2nd Icon from the Left at the Top of the PDF page.**
>>Has the Carburetor been Soaked and Cleaned?
>>From your Description it Sounds like the Needle Valve is Not Adjusted Correctly, a Bad Diaphragm or the Pickup Tube Screen is being Restricted.
>>Did you Adjust the Needle Valve?
>>Turn Clockwise Until "SNUG". ***Be Careful and DO NOT JAM the Needle Valve.***
>>Now Turn Counter Clockwise 1 1/2 Turns.
>>Start the Engine.
>>Now Carefully Using your Finger, Rev the Engine Using the Governor Linkage and Adjust the Needle Valve so the Engine Revs Correctly from Idle to High RPM's.
>>If this is Set Correctly and the Problem Still Exists, then
>>I Suggest you Remove the Tank and Carburetor Assembly from the Engine.
>>Remove the Choke Link Cover and Remove and Replace the Diaphragm.
>>Remove the Needle Valve and Brass Seat (if Applicable). **Some Model Engines use a Plastic Seat that Pushes into the Carburetor and Older Models have a Brass Seat that is Screwed into the Carburetor.**
>>The Plastic Pickup Tube can be Removed (but is NOT Required) from the Carburetor by Turning them Counter Clockwise.
>>Then Blow them Out with Compressed Air. This will Usually Clear the Pickup Tubes Screens of Obstructions.
>>**Never Reuse the Old Diaphragm on this Style Carburetor if you have to Disassemble the Carburetor.**
>>What is the Engines Compression?
>>If the Compression (with the Engine Cold) is between 90-100psi, then the Engine Requires a Re-Ring (Rebuild).
>>Is the Flywheel Key Damaged?
>>The Following is the Instruction File I Made for Removing the Flywheel from Most Mower Engines for Replacing the Flywheel Key, the Stator/Charging Coil/Magneto and the Point Set on Older Engines without Electronic Ign Coils.
>>It is the Basics and if you have a Question, Please Ask. Any Input to Make this File Better is Appreciated.
>>***Disconnect the Coil Wire from the Spark Plug. Remove the Blower Housing (metal engine cover).
>>Remove the Coil.
>>Remove the Flywheel Nut or Starter Cup (Depends on the Model).
>>Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel.
>>Tighten the Puller.
>>Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft.
>>On Some Models you Can Not Use a Puller and and the Jaws of a Standard Puller will Not Fit. On these Type Engines you can Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel.
>>**BE CAREFUL DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** >>Now Hit the Pipe Cap that is on the Crankshaft (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft.
>>*** Be Sure you have the Flywheel Torqued to the Proper Torque (if this engine is Cast Iron Block then it Requires 100ft Pounds of Torque for the Flywheel Nut and 55ft Pounds if it is the Aluminum Block Engine) and Set the Coil Gap to .020in..***
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 3 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
