QuestionQUESTION: JOHN, I HAVE AN OLD LAWNBOY MOWER MODEL#R7266 WHICH HAS BEEN IN THE FAMILY SINCE NEW AND HAS DEVELOPED A PROBLEM LAST SEASON WHICH I HAVENT BEEN ABLE TO SOLVE. THE PROBLEM IS WHEN FIRST STARTED THE MOWER HAS POOR POWER, CANT FIND A STEADY IDLE, AND POPS OR BACKFIRES. AFTER A FEW MINUTES IT WARMS UP AND WILL RUN OK. THE PROBLEM HAS PROGRESSIVELY BECOME WORSE. IVE CLEANED THE EXHAUST PORTS WHICH SEEM TO BE GETTING A BUILD UP ON A REGULAR BASIS LATELY. IVE DISASSEMBLED AND CLEANED THE CARBURETOR A FEW TIMES AND EVEN REPLACED IT WITH A SPARE CARB I HAVE BUT THE PROBLEM PERSISTS, SO IVE ELIMINATED A CARB MALFUNCTION. IVE ALSO DISASSEMBLED THE GOVERNOR AND REPLACED THE GOVERNOR COLLAR WHICH SEEMED TO BE WORN. IVE REPLACED THE SPARK PLUG AND USED FRESH FUEL BUT THE PROBLEM PERSISTS. I'D APPRECIATE YOUR THOUGHTS ON WHAT THE PROBLEM COULD BE. MUCH THANKS.
ANSWER: Hello Charlie:
>>From your Description it Sounds like a Compression Problem.
>>What is the Compression on this Engine?
>>Low Compression will cause the Problem you Described and the Statement "After it Warms up will Run OK" is a Good Indication of Low Compression since you have Eliminated the Carburetor and Exhaust Ports as a Possible Cause.
>>You may be able to View a Breakdown/IPL of the Mower at this Site Addy, https://lookup3.toro.com/partdex/default.cfm?xCaller=LawnBoy and Select Start Parts Viewer. Then Enter the Model Numbers (R7266) and Click Search. Then Select View Assembly Drawings. Then Select the Component you Wish to View.
>>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 5 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
---------- FOLLOW-UP ----------
QUESTION: JOHN , THANKS FOR YOUR QUICK REPLY. LOW COMPRESSION COULD DEFINITELY BE THE PROBLEM TAKING INTO CONSIDERATION THE AGE AND THE USE THE MOWER HAS ENDURED. JUST A FEW QUESTIONS PLEASE. IF I CHECK THE COMPRESSION ,WHAT WOULD A POOR READING BE? IF IT DOES IN FACT HAVE LOW COMPRESSION COULD IT BE CORRECTED BY REPLACING THE PISTON AND RINGS OR WOULD CYLINDER WEAR PREVENT THIS FROM CORRECTING THE PROBLEM? WHAT ARE OTHER POSSIBLE CAUSES OF LOW COMPRESSION? FOR A MOWER OF THIS AGE AND WEAR ,GENERALLY WHAT WOULD IT TAKE TO FIX A LOW COMPRESSION PROBLEM? THANKS SO MUCH FOR SHARING YOUR TIME AND KNOWLEDGE. CHARLIE
AnswerHello Charlie:
>>Other than the Seal between the Jug and Block Leaking and the Rings, there is Nothing that would cause Low Compression on 2 Cycle Engines.
>>The Cylinder Compression should be No Less than 100psi. Some Engines have Idling Problems at 90psi, but will Run Correctly Otherwise.
>>You need to Mic the Cylinder and Piston for Wear. There should be Not More than .005in to .010in Clearance between the Piston and Cylinder.
>>Usually if the Piston to Jug/Cylinder Clearances are with Tolerances, then Rings will Correct the Low Compression Problem.
>>As Always, 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 5 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
