Small Engines (Lawn Mowers, etc.): Smoking Kawasaki V twin, twin cylinder engine, compression test results

Question
Hi Paul,
I have an Exmark Lazer Z HP zero turn radius lawn mower, model# LHP4417KA, Serial# 350791. It came equipped with a Kawasaki FH500V twin cylinder engine, Code# FH500V-FS10, E/NO# FH500V862245. This mower is around a 2002 model. The engine started smoking heavily. It runs fine until it eventually fouls out the plug in one cylinder. I checked compression an it was good and equal in both cylinders. I removed the valve covers and checked the valve adjustment and it was in spec according to my service manual. I suspect a valve problem, but I'm not sure what to do next. Any suggestions you may have would be greatly appreciated.
Thanks,
Tony

Answer
HI TONY

CAN YOU RULE OUT  OIL LEVEL BEING TOO HIGH  
IS THE SMOKE COLOR  BLACK ( EXCESSIVE MIXTURE )RICH     OR BLUE / WHITE  ( BURNING OIL)?

ARE THE IGNITION UNITS  FIRING ON BOTH CYLINDERS  , WITH NO MISFIRE OR BREAKDOWN UNDER RUNNING CONDITIONS?

VALVE CLEARANCE SHOULD BE 0.006"  IN / EX  

IS THE BEATHER  FUNCTIONING PROPERLY?   NOTE   IS THE OIL SEAL UNDER FLYWHEEL STILL IN PLACE
HAVE SEEN THEM POP FROM A BIG BACKFIRE   AND LOSE ENGINE VACUUM    MIGHT PAY TO CHECK  ?  

IF ITS NOT WORKING PROPERLY  NO VACUUM IN C/CASE AND OIL WILL BE ALLOWED TO BLOWN BACK INTO
AIR FILTER BYPASS , IF  BREATHER STICKS / STUCK  PRESSURE BUILD UP AND OIL IS FORCED PAST RINGS AND GETS BURND IN COMBUSTION CHAMBER

WHAT ARE THE COMPRESSION TEST RESULTS   ARE THEY EVEN  BUT LOW ? ON 1  OR BOTH CYLINDERS


IF SO  INTRODUCE SOME ENGINE OIL INTO  EACH COMBUSTION CHAMBER 1 AT TIME -NEAR TDC  COMPRESSION STROKE( CLEAN MOTOR OIL USE 1 2 TABLESPOONS  NO MORE ) LET IT SIT FOR COUPLE OF MINTUES
RETEST EACH CYLINDER AGAIN  AND RECORD RESULTS

IF CYLINDER(S) ARE NOW UP WERE THEY SHOULD BE  COMPRESSION WISE   - WOULD SUSPECT  RINGS

IF COMPRESSION  RESULTS ARE NOT MUCH BETTER THAN BEFORE YOU PUT OIL INTO CHAMBERS
I WOULD SUSPECT - BLOWN HEAD GASKET(S) BURNT  VALVES OR SEATS  INTAKE  OR EXHAUST
LEAKING VALVES  IN / OR EX

THIS IS PROVIDED  BREATHER CHECKS OUT AS FULLY FUNCTIONAL AND OIL LEVEL CLEAN AND AT CORRECT LEVEL AND COILS ETC ARE GOOD AND FLYWHEEL TOP SEAL IS IN PLACE ( NOT POPPED OUT)

IS THE INSIDE OF THE AIR FILTER WET WITH A LIGHT OILY COATING ? MAY INDICATE BLOWN HD GASKET

THE BEST WAY TO HEAR / FEEL IF HD GASKET OR VALVES ETC ARE LEAKING/ BURND/ BLOWN
IS TO DO A LEAK DOWN TEST

BY INTRODUCING COMPRESSED INTO EACH CYL @ TDC COMPRESSION STROKE AND LISTENING FOR LEAKAGE PAST INTAKE VALVE @ CARB AND PAST EX VALVE @ EXHAUST , AND  FOR ANY EXCESSIVE PAST RINGS @ OIL FILLER CAP ( EVERY ENGINE WILL HAVE SOME PAST RINGS, BUT NOT TOO MUCH )AND FOR BLOWN HEAD GASKET BY LISTENING @ PUSH ROD TUNNEL , AND ALSO BY SPRAYING CRC AROUND CYL GASKET  YOU WILL SEE  CRC BEING BLOWN BACK / BUBBLING

YOU MENTINED PLUGS FOULS UP  -  CHECK FOR  BAD COIL 1ST  THEN  BLOWN HEAD GASKET


CHEERS   PAUL

LET ME KNOW IF THIS HELPS  AND WHAT YOU FIND


HOPE HAVE NOT CONFUSED  YOU