It wants to idle around 2k which still creates enough thrust to keep the plane rolling... How do I get it to idle lower where I will not have to phyiscally restrain the plain to stop it from rolling? I have a 31 cc twin ring ryobi with a zama carb, stock muffler, and C&H ignition.

There is a low speed stop screw on the carburetor that might help.

Hi!
Many of the Zama carbs have two small holes in the throttle butterfly. Check to be sure you don't have one of these if all else fails. ......Bob

Ya there is two holes one off center and half a hole on the edge... what do you folks recommend? Should I just get a large bore carb or do those also come with two holes?

If it's a brass plate, solder over the hole and fill the other with solder and file fit. Should be able to shut the engine off with the butterfly.

Take the diaphrams out and flip them over. Just kidding, some of these carbs do not have a low speed idle adjustment but they all have an idle position stop screw.

Fly at a location that has longer grass

One of my friends suggested holding the airplane vertical with tail up and cutting the grass. Didn’t seem like a good idea at the time.

Johnny what was the minimum RPM after the changes?

Does anyone know what minimum RPM might be expected on a Ryobi?

Bill

Mine will idle between 1850 and 2050. depending on the day and how IT feels. Using a 16-8 MAS. Comment above re: using idle screw was not an option for me as I use the throttle kill as I did not put a ignition kill on this plane.

I also put in quite a bit of neg expo (reduced sensitivity) on low end of throttle. Seemed to help.

The early WW1 Le Rhone rotary engines had no thottle. They ran at full thottle all the time and you slowed it down by turning off or blipping the mag. Maybe you could install a servo to operate a kill switch and you could blip the mag to help slow it down. I converted a Ryobi and get about 2000 rpm on idle and was wondering if that would be too high for my Senior Telemaster?? It will be ready this spring so I will know then.

I went down to local small motor shop and asked to see one of their walbro carbs and noticed it only had 1 hole on the side of the butterfly valve. So i soldered the center one shut on my zama. I think it idles roughly the same maybe 100-200 rpm lower. I don't have a tach to check yet.

No idle set screw that has already been removed. I can kill the motor with throttle or the battery switch for the electronic ignition.

I'll play with the low end adjustment on the carb some more, but other than that I think I'm just gonna have to learn to live with it. Maybe put a leash on it and walk it from the pits to the runway...

My theory is that a little rpm never hurt...just prop it to compensate it a bit...
Try using a lower pitch prop but with thick airfoil blade like the Bambula 18x6.

Depending on your airframe...your little Ryobi may love the 18x6....I fly 18x8's on mine.
And yes...they still pull a little even at idle, I just crank my tail wheel down a bit to add a small "brake" effect.

Good Luck!
CrazyHerb

On glow airplanes I have sometimes put a little friction on the main wheel hubs to prevent long landing roll outs. The friction never seemed to hurt take offs. Also putting a little toe in on the wheels will sometimes slow the roll.

Bill S

Someone may have a way to put the clutch back on the engine.