Small Engines (Lawn Mowers, etc.): FD750 Kawasaki water Cooled To Z Master, blown head gasket, kawasaki engines

Question
I have a Toro Z Master Model Number 74213 (serial number 210000465

This mower overheated last summer but didn't appear to damage the engine. It ran fine and mowed fine right up to the end of the mowing season. However, the last couple of times I  mowed, It would lose significant power when I engaged the mower. I am looking for help as to where to begin looking for the problem. Can you  help me?

Answer
HI  DERRYL

PLEASE FIND WEB SITE  FOR PARTS I/D
http://www.partstree.com/parts/?lc=kawasaki_engines&mh=26,51

CHECK YOUR OIL LEVEL AND CONDITION  AND CHECK COOLING SYSTEM FOR DEBRIS AND BLOCKAGE MAY NEED CLEAR OUT

DOES UNIT HAVE GOOD OIL PRESSURE  ?

IS CARBY FUNCTIONING CORRECTLY ?CLEAN AND FUEL FLOW GOOD FROM TANK TO PUMP AND PUMP TO CARBY

HAS SOMETHING OBSTRUCTED ONE OF THE NOZZLES OR MAIN JETS IN THE TWIN BARRELL CARBY ?

1 PLACE TO START LOOKING IS   ARE BOTH CYLINDERS FIRING ?
NOTE IF 1 OR OTHER EX PIPE ARE NOT HOT   THEN THAT CYLINDER IS NOT FIRING AND IS FUEL IS BEING PUSHED BACK THROUGH CARBY WHEN CRANKING

BUT IF BOTH FIRING AND PIPE IS NOT HOT  - CHECK VALVE ROCKERS / PUSH RODS / VALVE CLEARANCE ETC UNDER THE VALVE COVERS

THEN CHECK COMPRESSION  BOTH CYLINDERS SHOULD BE WITHIN 20 TO 25% OF EACH OTHER
IF COMPRESSION SEEMS LOW ON 1 CYLINDER IT COULD BE RINGS  OR  BLOWEN HEAD GASKET

COULD TRY DRY COMPRESSION TEST 1ST  REMOVE BOTH PLUGS, GROUND BOTH PLUGS KEEP GROUNDED
COMPRESSION TEST EACH CYLINDER   AND RECORD RESULTS

THEN POUR 1 OR 2 TABLESPOONS OF ENGINE OIL INTO EACH CYL  ( 1 AT A TIME )
THEN RETEST COMPRESSION AS YOU DID BEFORE  RECORD RESULT  
DO SAME FOR OTHER CYL AND RECORD RESULT

IF 1ST TEST SHOWED  1 CYL NORMAL COMPRESSION  AND OTHER CYL LOW COMPRESSION
SECOND TEST SHOWED  THAT  CYL WITH LOW COMPRESSION NOW AT ABOUT NORMAL  -WORN RING OR PROBLEM WITH THAT CYL     BUT IF WET TEST DID NOT INCREASE VERY MUCH AT ALL THEN LEAKING VALVES OR BLOWN HEAD GASKET INDICATED  LOOK TO THAT CYLINDER FOR PROBLEM


IF YOU HAVE ACCESS TO  LEAKDOWN TESTER    -  TEST  CYLINDER @ TDC COMPRESSION  STROKE , YOU WILL HEAR ANY  AIR ESCAPING PAST RINGS INTO C/CASE @ OIL FILLER CAP,  AND AIR PAST INLET VALVE SEAT @ CARBURETTOR OPENING  AS WELL AS EX VALVE LEAK @ EX PIPE , YOU WILL SEE A BLOWN HEAD GASKET IF YOU SPRAY CRC ONTO THE JOINT ON THE CYL HEAD AND BARRELL,    
WHILE ROCKER BOX IS OFF YOU MIGHT TRY AND SEE IF CAN HEAR THIS HISS OR SEE PLUME OF AIR ESCAPING FROM BLOWN HEAD GASKET FROM COMBUSTION CHAMBER INTO P/ROD TUNNEL  ?  


CAN YOU LET ME KNOW  WETHER  TYPE NUMBER IS FD750-****   IE   AS05 OR BS03 ETC  

CHEERS  SEE WHAT YOU CAN FIND FROM BASICS

F = FUEL
A = AIR
C = COMPRESSION
T = TIMMING
S = SPARK

CHEERS PAUL