OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Trimmers and Brushcutters Two Stroke Trimmers & Brushcutters HELP!!! Ryobi Scrub Hornet.

Hi Guys,
I'm having a look at a scrub hornet at the moment, and it's giving me a bit of trouble!

Its an older Ryobi, with a Walbro WA 103.

Got a new could into it, and cleaned up the carby, new filters, gasketa nd diaphrams all good.

Got it started, and tuned the idle and low, now it's Idling well... But i cant get it to rev, at all!

It tries... a tiny bit, but not really, just gets rough at full throttle, but no speed, not even able to engage the clutch.

Iv'e cleaned it all out, checked and adjusted all mix screws, looked into the throttle, opens fine!

What could be stopping it getting its revs up?

Mr Davis,

1.Did you replace the fuel filter in the tank?

2.Did you try running it without the muffler?

3.Did you check that the rings have movement?

Ryobi machines tend to build up carbon behind the rings and that causes issues.

Mud wasp nest in muffler outlet Easy fix

Aren't they a bit costly though, Joe? I think my line trimmer would really love a set, but for a $20 line trimmer, it seems cheaper to put up with it not being all that easy to start.

The diaphragms are OK, i pulled a known good carby (Exact Match) of another trimmer, and, i even put this ones across to the known good trimmer, and it worked fine.

I will look into the muffler side of it, and the rings when i return to Dubbo in a fortnight, i will be taking some rings and a muffler i have here up with me, and i will report back when i see how that goes!

Ty, you can usually deal with the muffler question by just removing it and running (briefly, with hearing protection) without it. That also gives you the chance to look at the piston through the exhaust port, to check for scoring. It is true that a port-controlled two stroke will not give the correct power without the exhaust system in place, but it will start and run.

I have seen the same issue with the muffler beign blocked up by carbon, unfortunately I couldnt find a way to pull it apart so I replaced it with one from a trimmer that snapped a conrod.

I have never had a lot of luck with the tiny carbs, They are too small and fiddly for me, I will tinker with one at a push though.

When i get up there i will be running it without to get an idea if this is the issue, I just didnt get a real good look at the muffler before i left, so i cant say what it will need.

I hve so many of these sitting around, cant hurt to throw one in the toolbox (Heck, i might take one of my spares engines)

In the meantime, here's a few pictures of it, i forgot i had grabbed them, its an old straight bar Ryobi Scrub Hornet, with bull horns, no to bad a machine fro a ryobi, it belons to my Father-in-law to be, and it was his fathers before that.

I dont know if the throttle is original, seems like an old bike gear adjuster, it was pretty good while doing diagnostics though, as it alowed me to set the trottle in varios positions while making adjustments.