I HAVE A 31CC RYOBI LEAF BLOWER ENGINE WITH A SIDE MOUNTED ZAMA CARB. I HAVE IT MOUNTED ON A ULTRA STICK LITE BY J.R. I PUT THE SMALL FUEL LINE ON IT THAT FIT THE CARB NIPPLES WITH THE PRIMER BULB. IT STARTS EASY BUT I CAN'T GET ANY POWER OUT OF IT TO FLY THE STICK VERY FAST, IT BARELY KEEPS THE PLANE IN THE AIR. I'M RUNNING A 16-8 ZINGER PROP ON IT. THANKS FOR THE HELP

What are you shouting about? Using all caps in email/internet messages is considered shouting.

The carb is most likely too small?

We mostly have to put a larger carb on leaf blowers and weed whackers.

Most chain saws already have pretty good carbs.

I've had good results using a Zama C1Q-M33D carb on the last few Ryobi 31cc conversions that I've done. This carburetor is reasonablly priced and can be found on *bay or I believe Scott at Brillelli carries them also. When set-up properly, this engine should produce 7000-7500 RPM with a standard Zinger 18 X 8 prop.

Just a side note, do not use a prop that allows your Ryobi to rev beyond 8000 RPM.

Hope this helps,

Capped

Side mounted carb suggests it's a Homelite engine. If it has a C1Q ZAMA with fixed high end needle you'll never get enough power out of it, as it will run lean no matter what modification you make. I've been there and done that, same goes for the stock Walbro carbs on th 31cc trimmers. Fit a WA-167 and the problem will vanish with little tuning.

The other thing to look at is the porting. Comparing Homelite 25cc and 30cc cylinders I've noticed the exhaust porting is significantly different (can't remember which way). Using the exact same setup, excluding cylinder/rod/piston swaps, my 25cc will turn 8000rpm with a MA 16x8. By comparison the 30cc setup will not go over 7700rpm. With some research and careful porting you should be able to get the 30cc jug to run as hard (and harder) than the 25cc.