QuestionQUESTION: hi i think i sent my reply to the wrong person this was my reply.
Hi again i tried taking off the muffler and starting the trimmer again still the same.I did notice where the muffler joins to the engine had fuel was wet with fuel but when i took the plug out it was dry.I looked into the top of the piston through the spark plug hole and it looked moist.I have now since stripped the carb and got it cleaned the boy pressure tested the carb also and it did not drop.I am just home and i have now just checked the piston and barrel no sign off scratches.
thanks shaun
ANSWER: Hello Again Shaun:
>>No Worries. It Happens.
>>If you are Sure the Spark Plug is Firing, then the Carburetor Metering Valve Lever is Set Too High and Requires Setting.
>>When the Metering Valve is Too High, it Allows too Much Fuel to Enter the Engine and Effectively Floods the Engine.
>>The Metering Pump Diaphram is Under the Carburetor Plate with 4 Small Screws in it.
>>The Dowl on the Diaphram should Just Touch the Metering Jet Actuator Arm.
>>The Actuator Arm is Adjusted by Carefully Bending the Actuator Arm Up or Down to get the Correct Clearance.
>>****All the Carburetor Adjustments are the Same for Lawn Mower and Trimmers.
>>If the Main Air and Idle Air Mixture Screws are Side by Side on the Side of the Carburetor, then the Idle Air is Nearest the Engine.
>>****Turn the Idle Air and Main Air Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.****
>>If you have Questions, Please Ask. The links above Provide Good Directions on Cleaning the Carburetor. Make sure you use an Compressed Air to Blow through all the Carburetor Passages to make sure they are Clear.
>>1- http://www.repairfaq.org/samnew/lmfaq/lmclctc.htm
>>2- http://www.cpdonline.com/692509.pdf .
>>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 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. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hi again i had the carb cleaned the other day and it was blown with an air hose after it was cleaned.I have just checked the diaphram and the actuator they look fine.
What if i shut the fuel to the carb and put fuel into the piston chamber and try to start it if it doesn't start and it still backfires would that rule out its the carb and more a timing issue?
AnswerHi Again Shaun:
>>Since you are Confident the Carburetor is Clean and Set Correctly, then
>>Check the Flywheel Key.
>>The Following is a Basic Instruction File I made for Removing the Flywheel and Replacing the Flywheel/Flywheel Key.
>>Remove the Cover that Houses the Starter Assembly.
>>Remove the Spark Plug and Use a Bolt the Same Diameter and Threads as the Spark Plug and About 3" Long.
>>Thread the Bolt into the Spark Plug Hole Until it Engages the Piston.
>>Slowly Tighten the Bolt Until you have Locked the Piston and it Does Not Move. **BE CAREFUL A LOT OF TORQUE IS NOT REQUIRED. PISTON DAMAGE CAN OCCUR IF TO MUCH TORQUE IS USED ON THE STOP BOLT**
>>Now Remove the Flywheel Nut.
>>Use a 3 Jaw Puller and Attach the Puller to the Flywheel.
>>Look for a Puller with Flat Jaws. These Slide Under the Flywheel and Allow for Easier Removal.
>>Tighten the Puller and then Hit the Puller with a Hammer. Tighten and Hit Again Until the Flywheel is Loose and Can be Removed from the Crankshaft.
**Note the Key that Aligns the Flywheel to the Crankshaft.**
>>This Key is Most Likely Sheared or Bent and Causing the Plug to Fire Slightly Out of Time and Causing a Compression Lock. There is Not Enough Compression to Kick Back But Enough to Cause the Engine to Seem to Have High Compression or it May Seem to have Low Compression and Not Backfire at All.
>>**Some of the Newer Units have the Flywheel Key as a Part of the Flywheel and the Complete Flywheel has to be Replaced.**
>>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 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. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
