Top 10 Homelite Mighty Lite Lawn Trimmer Questions & Answers

Had same problem with my reconditioned unit. After a few hours engine would run only with 1/2 choke and full throttle. Like most 2 cycle engines, the unit was starving for gas.

Solution: Adjust both carburetor screws. These screws are located directly below the idle adjustment screw. There are 2 of them side-by-side and they are approx. 3/16 diameter with an oval shaped cast metal raised restricter. Simply remove the plastic round air filter by removing the small nut. Then, using a Dremel tool while wearing safety glasses, cut a slot in the face of each screw. Cutting through the raised cast metal surrounding the screws will not damage the unit. Then using a small flat blade screwdriver, screw each screw clockwise till it stops then back-out each screw 2 turns. Factory setting is 1 - 1/2 turn each. However, the unit over time runs too lean with the factory setting.

Then start unit, let warm up with 1/2 choke, then turn to run position and make any final adjustments.

Making this adjustment, I am once agin able to trim my yard in the idle position. Runs Great !!!! Hope this helps.

My UT21546 has 2 springs, the regular recoil one and a what I'll call a anti kickback one. the top of the anti kickback spring kept coming unsecured and finally I just deleated it alltogther and screwed the 2 plates tightly togehter and the near new unit works better than new now.

Hello roda551:

This can be a Carburetor Problem or an Exhaust Problem.
I Suggest you Check the Exhaust First and then the Carbuertor.
From your Description it Sounds like the Exhaust Port or Muffler is Restricted with Carbon Deposits, the Carburetor Metering Pump Actuator Gap is Incorrect.
>>The Following is a Basic Instruction File for Doing a Diagnostic on the Engine for this Problem. Any Input is Appreciated.
>>**Remove the Muffler and Make Sure the Exhaust Port is Clear.
>>If it is, then Try to Start the engine with the Muffler Off.
>>If it Starts and Runs Properly, then Clean the Spark Arrestor Screen in the Muffler or Replace the Muffler if Required.
Is the Fuel Line from the Fuel Filter Staying Full of Fuel?
The Carburetor Metering Jet Actuator is Set so the Pump Diaphram Dowl is Just Touching the Actuator Arm. These Components are Located Under the Cover with 4 Small Screws Holding it to the Carburetor Body.
Try Setting the Carburetor Air Mixture Screws.
>>The Following is the Instruction File for Setting the Air Mixture Screws. Any Input is Appreciated. The Procedure is the Same for 1 or 2 Mixture Screws, Just Use the Instruction File and Skip Over the Section with the Missing Mixture Screw ( Usually the H Mixture Screw).
>>Now Setting the Air Mixture Screws:
>>****Turn the Idle Air (L) and Main Air (H) Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Set the Throttle Full Open, Start the Engine.
>>Turn the Main Air (H) Mixture Screw Clockwise Until Proper Revs are Obtained. **Carefully Use your Finger and Move the Governor Arm to Rev the Engine (on Chainsaws and Trimmers Use the Trigger to Rev the Engine) Until you Reach Max RPMs (on Chainsaws and Trimmers, the RPMs are Not Set to MAX. Set to Max and then Reverse the Setting Screw 1/4 or 1/2 Turn. If the H Mixture Screw is Set too High; the Engine will be Starved for the Oil in the Gas and Damage the Piston and Jug/Cylinder) and the Engine is Running Proper at Full Throttle Up a Grade and for Chainsaws and Trimmers they Do Not Bog Down Under a Load. 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 (L) Mixture Screw so there is No Hesitation when Rapidly Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.****
If the Above Did Not COrrect the Problem, then Remove, Disassemble, Soak and Clean the Carburetor.
>>The Following is a Basic File I Made for Cleaning Carburetors. Any Input is Appreciated. Even though the Carburetor Looks Clean, the Internal Passages May be Restricted with Varnish that Gas Causes to Build Up over Time.
>>Spray Cleaners Remove this Varnish in Layers, so Soaking is the Only Sure Way to Remove ALL this Varnish.
>>I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning.
>>Remove Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed.
>>If you are Able to Remove and Disassemble the Carburetor and Keep the Gaskets Intact, then Usually these Gaskets can be Reused. The Only Parts you May Need to Replace are the Needle Valve and Metering Pump Diaphram.
>>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.
>>If you Order a Kit, then Replace All the Old Components with the New Ones in the Kit even if the Old Parts Look Good.
>>Once Disassembled, then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts.
>>Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air.
>>***(Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***.
>>****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 .
Please, Do Not Hesitate, If you Hit a Snag or this Does Not Correct the Problem, I am 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 Be Happy. Thanks.

Good Luck

Respectfully

jbridger (John)

http://www.fixya.com/support/t2258508-homelite_mighty_lite_26ss_weedwacker

the problem with it is its a piece of **** excuse for a line feeder if its a mighty lite. mine is new and in perfect condition and getting it to feed string is close to impossible.

Hi,
Check the primer bulb for cracks,it will not pump gas if it is torn or cracked. Then check line from bulb to gas tank to see if there connected or are broken.

I sounds like it sucked up some debris in the bottom of the fuel tank and obstructed fuel flow somewhere. Start by blowing out the in-tank fuel filter (You will have to fish it out with something), then load the line with carb cleaner (wear safety glasses) put fuel filter back in line and crank it a few times to pull the carb cleaner into the carb. This may dislodge the obstruction. If this doesn't work, you will have to remove and cleant he carburator. Hope this helps.

I have the same problem with my MightyLite 26cc Blower/Vac. If it does start it runs rough on full choke and stalls on 1/2 choke or run. I've tried everything, fresh fuel, Seafoam, etc. Nothing works. First time I used it the exhaust burned a hole in my brand new Carhartt hooded sweatshirt. Best solution, throw it away, never buy another Homelite product and tell anyone who will listen what a piece of junk Homelite products are.

I have one of these. The mix is 25 to 1. Before starting use the primer bulb to get fuel through; it says to turn the choke to limit the flow, but I've found mine starts easier with the choke open. To start, flick to on/start position, hold the (safety switch?) flush with the spine, and give it a yank.

Bulb or fuel line could have a crack or a clog in fuel line/filter or carburetor. Here's a video on how to change the bulb and fuel lines and another video on how to clean/rebuild the carburetor.

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