Ryobi Trimmer Fix - No more Clogging & Motor Shutdowns!

Summary

There is a design flaw with the latest 40V Ryobi Trimmer head assembly.  Heavy grass, vine runners, or debris can wrap tightly around the shaft of the mechanism & trimmer head, creating a constant, high-friction brake that eventually causes the motor to shut off to prevent overheating.  It might also shorten your batteries' lifespan. The problem happens often enough that one spends more time unclogging the trimmer than trimming with it.  You can see a typical example of the problem in the photo shown below:

Which Ryobi Trimmer does this fix apply to?

The fix is compatible & tested with Ryobi model RY40CK201K trimmer combo consisting of:

• RY40PH01 (40V Power Head)

• A54ST01 (Straight Shaft Trimmer Attachment)

This fix may work with other Ryobi trimmer attachments, but I'm not able to confirm it.  Maybe other trimmer users can respond with their own experiences.

Why does it happen?

The problem with this particular Ryobi trimmer design is that there is a large gap between the gear head & the upper bump feed (head string housing). This creates a perfect opening for clippings to gather & get tangled. Additionally, the exposed notch on the Flanged Washer acts as a grab point, snagging tall grass & weeds & wrapping them tightly against the gear head & bump feed assembly as it rotates.  Eventually, the accumulation of debris will create too much friction & cause the motor to shut down. The figure below highlights the design flaw (marked in red):

The other figure below shows what the trimmer head looks like on a competitor’s product, which provides zero possibility of a similar problem occurring.

The add-on part presented in this design closes off the opening on the Ryobi trimmer head & prevents any debris from accumulating or getting tangled.

Why does the trimmer motor turn off?

Most cordless tools are equipped with internal thermal and current sensors that constantly monitor the motor and battery temperature and the power flowing through the system. When the current draw becomes excessively high or the internal temperature exceeds a safe threshold, the tool’s logic board will instantaneously cut power to protect the motor windings and the lithium-ion cells from permanent damage.

How to Install the Fix

Remove the Lower String Head Housing with Spool & Spring from the trimmer by pushing both retention tabs shown in the image below:

Now align the notch on the Gear Head with the notch in the Flanged Washer:

Place a 4- 5 mm drill bit in the opening & unscrew the Upper String Head Housing from the Gear Head by turning it counter-clockwise. Remove the drill bit once the parts are completely apart:

Remove both the Upper String Head Housing & the Flanged Washer from the gear shaft:

Insert the Flanged Washer into the printed part, noting the proper orientation & also making sure that the notch in the flange is aligned with the tab on the printed part. Refer to the image below. Also, make sure the flange is properly seated & inserted all the way into the part:

Insert the Flanged Washer & part assembly back onto the Trimmer Shaft, then rotate the assembly until the notch on the Flanged Washer re-aligns with the notch in the Gear Head:

Re-insert the 4- 5 mm drill into the hole & re-screw the Upper String Head Housing back onto the Gear Head by turning clockwise until things feel tight.  Make sure that the housing is properly secured onto the shaft.  Remove the drill bit once you are done:

Reinstall the Lower String Head Housing with Spool & Spring, and then you are done!  

Happy trimming with no clogging!