Rescue for a Weed Whacker




About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

This is a scanned photo of my weed trimmer. The centrifugal clutch inside the clutch housing (yellow square) came loose and chewed the plastic clutch housing to pieces so that the engine hung loosely from the throttle cable. I checked into getting a new clutch housing, but encountered only dead ends.

(The reason the clutch came loose was that I tried to open the machine so I could tighten up the starter cord. Doing that compromised the clutch's retainer. Although I tried to improvise something, it did not hold.)

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Step 1: A Better Clutch Retainer

This is an exploded drawing from the weed trimmer's manual. I added the colored items. The first step was to make certain the clutch bell (larger cylinder between the green and yellow boxes, right most of the three lines from #11) could not slide forward from the centrifugal weights assembly (#10) on the clutch bearing (smaller cylinder left of the green box) and the shaft connected to the engine (black cylinder portion in the green box). I drilled a hole (red circle) through the clutch bell assembly and just a little into the black shaft in the green box. I threaded the red hole for a set screw. I locked the setscrew in place with a tack weld. I filed the weld at the setscrew smooth so it does not rise above the surface of the clutch bell's shaft portion. If I ever need to remove the clutch, I will drill out the setscrew tack weld.

Step 2: Where to Mount an Improvised Clutch Housing

This is the same graphic from the previous step. Note the four holes in #5 (starter housing shroud) that receive screws #8 (follow the dotted line running through #7). These were used to mount an improvised clutch housing.

Step 3: Clutch Housing Mounting Tabs

When I needed to make this repair, I was much involved at a construction site. Pictured is an electrical panel. Notice the gray knockouts between the breakers. I gathered four of these from scrap materials on the ground. I bent each into an "L" shape. See the next step.

Step 4: The "L" Tabs for Mounting the Improvised Housing

Although this is actually a photo of the finished project, it also illustrates the "L" shaped knockouts from a circuit breaker panel. I drilled holes in both ends of the "L" pieces and mounted them with screws on the starter housing. Then I measured the space between the ends of the "L" tabs.

Step 5: Wood Block

I chose a piece of 2 inch stock with a fairly dense grain pattern and cut it to fit the open space between the four steel "L" tabs.

Step 6: Drill a Hole for the Boom

The boom is the metal tube that runs between the engine and the line spool and its head. I drilled a hole through the center of the wood block so the hole's diameter was the same as the outside diameter of the boom.

Step 7: Saw the Block Into Two Halves

Cut the block into two halves as shown. Notice the small circle on one face. Drill a hole for a long wood screw. Drill a like hole in opposite corner. These screws will clamp the block around the end of the boom to provide a rigid structure.

Step 8: Finished

This is another photo showing the completed project. The other photo of the completed project was in Step 4. By viewing both photos you can see the location of the screws that hold the two halves tightly around the end of the boom, as well as the saw kerf cut through the block to make two halves.

In this photo you can also see how a hole was made to accommodate and fit the throttle cable.

I have used this weed trimmer for more than ten years since making this repair and it has been as good as factory new. While the clutch now runs in open air inside the steel "L" tabs, it would be near to impossible to acquire an injury from the spinning clutch. You might never need to make this repair, but what I did might provide an idea for you for something you will need to do.

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    11 Discussions


    6 years ago on Introduction

    Rather impressive article with some good points! I think all these information are very helpful for rapire weed whacker or outdoor power tools.


    9 years ago on Introduction

    Nice improvisation with the materials at hand. Even though you've not yet been injured and can see no path to injury, it could still happen. It seems that your shaping pvc in the microwave instructable could provide a good method for building a guard if you so desire.

    A note on step 7... if you cut the block of wood in half, screw it back together and then drill the hole, the resulting hole is round and you end up with no visible kerf when installed. Of course you'd need to drill a hole slightly smaller than the boom to achieve a good 'clamp' on the boom.

    I know you're unlikely to modify this as you've been using it for "more than ten years", but just some ideas for others that may see this and think "I could use that idea to solve my similar problem."

    1 reply
    Phil BGoodluck

    Reply 9 years ago on Introduction

    Thanks for looking at various Instructables I have done.  Someone would need foolishly to poke his fingers into the clutch area to be injured by it, and then it would likely be a burn or a small cut from the edge of the clutch.  As soon as pressure on the throttle trigger is released, the exposed portion of the clutch stops by itself.  There would be more danger of injury from the whirling string when in normal use or from touching the hot muffler on the engine. 


    10 years ago on Introduction

    Bien, Phil! (¿alguien sabe cómo traducir al inglés la expresión "¡este es mi pollo!"?) Well, Phil! (knows anyone how to translate to English the Spanish expression "¡este es mi pollo!"?)

    5 replies
    Phil Brimar2000

    Reply 10 years ago on Introduction

    Rimar, Thank you for your comment. I did some searches on "¡este es mi pollo!" and found nothing other than a literal translation of the words, namely, "That is my chicken." But, I am sure it is an idiom with meaning beyond the bare words. I am guessing it would be something like, "It is my cup of tea." meaning "It fits my interests." Correct me, if I am wrong.

    rimar2000Phil B

    Reply 10 years ago on Introduction

    I suppose the phrase comes from Cockfighting, but I'm not sure. The meaning is "that is the person (or chicken) for whom I have bet all my money" or so. They say it as a compliment when a friend or relative achieves something important. It is a way of "taking" the achieving of the other. I suppose that English should have a similar saying, that possibly translated into Spanish does not make much sense.

    Phil Brimar2000

    Reply 10 years ago on Introduction

    Thanks, Rimar. I suppose in English we would say, "I am putting my money on him." or, when referring to another, "She is hitching her wagon to him."

    yokozunaPhil B

    Reply 10 years ago on Introduction

    There is an English expression similar that states "Don't put all your eggs in one basket" meaning don't bet everything on one idea. While they don't say the same thing exactly, it seems like too much of a coincidence to just be random.