Ryobi 'String Trimmer/BrushCutter'

Ryobi RBC26SESB

I pulled this previously useful little machine out of the shed today, to tidy-up the wild garden: Assembled the lower shaft onto the upper, and fired her up.

The motor runs fine, but there is no drive to the cutter-head

The [straight] lower shaft has a flexible drive with a square end (like an overgrown speedometer cable) and functions correctly BUT there is no drive to the square socket in the upper section. ...

Normally the shaft remains still at tickover, and then engages as the revs increase: This is presumably the action of a centrifugal clutch, and I can only assume that the clutch is broken, faulty, or worn-out.

The machine is [predictably] just out of warranty, but has only done a few hours actual work.

Before I start investigating ... Does anyone have experience of this problem and/or access to an 'exploded diagram' ?

Thanks

MichaelG.

Michael -

At risk of teaching my grandmother here, but are you absolutely sure that the telescoping sections of the lower drive shaft are fully home and seated as they are intended? I've got the same problem with a Stihl brushcutter where I change between different heads, but the square on the drive shaft doesn't readily line up with the square hole in the clutch so I have to fiddle with it each time to make sure the outer goes all the way home, and thereby the inner ends up fully home as well. It isn't at all obvious from the outside that the outer needs just another 10 mm of engagement for the drive shaft to enter its correct location.

It seems a bit unlikely that the clutch is actually the problem if it has only done a few hours work. Ryobi make some good stuff, I can't believe it isn't robust enough for the intended purpose.

Hope its a simple fix! Regds Simon

The manuals (and an exploded diagram) are on their website

**LINK**

Brian

I saw a similar trimmer a few years ago where the cup around the centrifugal clutch had moved forward out of position toward the cutter head by cutting its' way into the housing plastic! I think the original assemblers forgot a steel thrust washer between clutch cup and housing. Another trimmer I repaired last year had the primary speedo cable style driveshaft unwrap and shred, and I found the friction material on one side of the centrifugal clutch hub assembly partly separated from the aluminum hub. Best to disassemble and have a look. Only a few minutes work usually, likely need Torx bits. Not sure about UK but here in Canada we can get quite a few Ryobi parts either from local dealers or US dealers. Not cheap though - if you need a few parts, a new trimmer is often only a few $ more than the price of a few parts - wise to price check before buying parts.

BTW trimmer engines where the drives or cutter head have failed are great for car and boat models.....

9 times out of 10 will be the clutch. Like a pr of brake shoes. Less than a tenner out here for a quality set.

I have a couple of Honda strimmers/brush cutters and a lopping chain saw attachment. To my dismay, the chainsaw att. slid along the shaft and resulted in a loss of drive. I had to completely dismantle the drive shaft tube to be able to relocate the shaft at the clutch end and rebuild it forwards. No prolem since, but I will make sure that when I change back to the strimmer/brushcutter head I keep that drive shaft well seated!

Maybe I missed a trick somewhere, but those drive shafts are difficult to locate - they are long and don't have any support to centralise the far end of it. There is likely a workshop guide to make it easier. I look forward to any suggestions for the future.

.

Thanks, Simon ... Yes, that was my immediate thought, but:

1. The two sections are located by a sprung radial pin, so I can't see how the seating could be other than correct.
2. The square socket has a generous chamfer, so it is highly improbable [ I dare not say impossible ] that the square will miss the socket.
3. With the lower section removed ... the square socket in the upper section still does not rotate.

I haven't looked at it since posting the question; so I admit that may have missed something blindingly obvious.

MichaelG.

Edited By Michael Gilligan on 28/09/2018 17:25:00

.

Thanks, Brian ... Not something I would usually fail to look for !

... Just shows what a dose of frustration will do !

MichaelG.

Jeff, thaiguzzi, and ndiy ... Thanks for the additional thoughts

I will investigate sometime in the next few days.

MichaelG.

I have one of these as well and from new to get the heads to run after changing I have found that by pulling the drive spindle out as far as it will come and then carefully pushing the driven end over the square gets it running 9 times out of 10. As Simon says it need that bit of extra length to engage.

Edited By Dennis D on 28/09/2018 17:31:07

That's food for thought, Dennis ... Thank you.

MichaelG.

I'm sure your model has similarities to the PBC3046YE Model I used to have. I never had an issue with the drive link, attachments etc, but I did find the clutch drum suffers with fast wear despite all moving parts being meticulously cleaned regularly.

The final problem I had was the loosening of the crankcase screws (3) coming loose and lost case compression. Up to that point, it was a good machine for 3 years.

As you're UK based, you may find this link handy should you need to obtain any parts-

Shoulders

I would take the engine off the clutch housing and check that the clutch shoes have not frozen to the pivot shaft .

while you have it off you can easily check the rest of the driveline for faults by holding onto the clutch bell and get someone to try and turn the cutting head - if it slips or jumps you have problems !