Small Engines (Lawn Mowers, etc.): Briggs & Stratton governor, john deere js63, briggs stratton

Question
I have a walk behind lawnmower, John Deere JS63, family: YBSXS 1901VC 274652; product ID: GXJS63X050571; date code: 050300; and apparent serial # 7 59936 10162 5.  I bought the machine used from a neighbor, and discovered when it goes into heavier mowing, the engine dies down.  It does not rapidly speed up, but slowly returns to the higher rpms when I remove the load.  It seems as if the governor is not working or disconnected.  The linkeage to the carburator throttle is in place on the carburator end.  When not running, it will stay wide open, but when it starts, it closes to the adjustment screw.  Any suggestions?  Thanks.

Answer
HI DON

SOUNDS LIKE THE GOVERNOR SPRING HAS COME OFF THE GOVERNOR ROD LOOP OR THE CARB END  OF THE GOV SPRING HAS BEEN BENT INWARDS AND IS NOT PULLING THE THROTTLE PLATE OPEN

LOAD IS EXCEEDING TOP NO LOAD SPEED ( WHICH IS  3300 RPM  WITH NO LOAD ON ENGINE )

WITH ENGINE RUNNING, OPEN THROTTLE TO FULL  AND BEND LEVER ARM WITH THE GOVERNOR SPRING ON IT( AT THE CARB END )  OUTWARDS THIS SHOULD PUT MORE OPENING FORCE ON THROTTLE LINKAGE AND OPPOSES  CLOSING FORCE OF GOVERNOR      USE REV COUNTER TO CHECK REVS   

THE GOVERNOR LEVER AND ROD MOVE TO CLOSE THE THROTTLE WHEN RUNNING  
THE GOVERNOR SPRING ATTACHED TO LEVER AND THROTTLE CABLE  ACTS TO OPEN THE THROTTLE PLATE  

THE SPRING BALANCE BETWEEN  GOV CLOSING FORCE AND THROTTLE OPENING FORCE IS THE GOVERNED SPEED

WHEN THE ENGINE IS STOPPED  THERE IS NO CLOSING FORCE APPLIED BY THE GOVERNOR TO THROTTLE PLATE AND THROTTLE PLATE WILL MOVE TO FULL OPEN WHEN ENGINE IS STOPPED   THIS IS NORMAL

WHEN LOAD IS APPLIED TO ENGINE IE MOWING GOV CLOSING FORCE IS LESSENED  AND GOV SPRING FORCE OPENS THROTTLE MORE IN RESPONSE TO LOAD  

WHEN LOAD IS REMOVED  IE  GONE THROUGH THICK PATCH OF PATCH  ENGINE SPEED INCREASES AND SO DOES GOV CLOSING FORCE AND MOWER SETTLES BACK TO GOVERNED SPEED

TRY ADJUSTING GOVERNOR

LOCATE GOVERNOR ARM ,( THIS COULD BE UNDER THE FLYWHEEL / STARTER COVER  SO YOU WILL HAVE TO REMOVE TANK AND STATER COVER ASSY )  LOOSEN NUT CLAMPING THE ARM TO SHAFT, TURN THE GOV SHAFT ANTI CLOCKWISE FULLY AS FAR AS IT WILL GO  , DO NOT FORCE ,  WHILE HOLDING THE THROTTLE PLATE  AT FULL OPEN THEN TIGHTEN THE NUT CLAMPING THE GOVERNOR ARM

HERE IS BRIGGS WEB SITE  

http://www.briggsandstratton.com/maint_repair/manual_and_more/

ENTER THE BRIGGS  MODEL AND TYPE CODE OF ENGINE COVER  AND  DOWNLOAD A PARTS LIST FOR IT
GOOD SITE LOTS OF INFO  

CHEERS HOPE IT HELPS

PAUL