I have a Ryobi from my Son-In-Law's old string trimmer that I have had for a few years. it ran great when in the trimmer with the exception of the carb. The company bought him a new trimmer and I got the motor. I have the new flywheel cut and balanced, and the engine prety much set. I need to get a new carb for it though, and want to get a Walbro carb. Does anyone know a model number or size? I plan on putting this on a Great Planes Giant Big Stik. Thanks for all the help in advance. Here is a pic of the Zama,

Duh,,, sorry about the double post of the pics, I havn't done this in a while!!

A Walbro with a "28" or "27" cast into the venturi would be ideal These are basically &/16" venturi carbs.

The most popular number for this size carb is WA167-1

But there are many more.

There is a list on here if you look down a ways.

If not, I can PM one to you.

Here's alink to the list....

http://www.rcuniverse.com/forum/m_3811393/tm.htm

Enjoy,

Jim

Thanks for the info, Just what I needed.
Bob

Here's another link you will like. it is about the Ryobi and the ZAMA carbs that are the right size.

http://www.rcuniverse.com/forum/m_3810026/tm.htm

Enjoy,

Jim

Thanks, I will make sure to save these links.

I have received and gone over the lists of carbs, both Zama and Walbro, but when looking for the carb that I have, I do not see it listed. I have seen other carbs, but what I belive to be the vent hole will not match up with the back plate. Here are some pics of my Zama and the back plate. Any ideas? Is that a vent hole that must match up with the carb? Just consider me new, and confused!

If you mount the carb with the pump part (The side the vent hole is on) towards the cylinder it will align perfectly.

Enjoy,

Jim

The Zama carb on your Ryobi has a 5/16" venturi and in metric terms that is 8mm. All the carbs in the Zama and Walbro lists are 11mm or 7/16". This is the size you want to go to so you will have a good airplane engine.

Enjoy,

Jim

Look up your carb here....

http://www.zamacarb.com/prodlist.html

The number shown on the mounting flange of your carb "P10 5Y0" is not the model number of the carb. The model number is on the side of the carb.

Enjoy,

Jim

No wonder I couldn't find it anywhere! I do see "C1U on the side by the needle valves.
Thanks

One other thing.....

If you have a carb with the two fuel lines instead of one....

The smaller line (or the one that went to the finger pump) must be plugged with a piece of fuel line and a bolt if you are not using the little finger pump.

Without the finger pump, the carb will suck air through this line.

If you have trouble figuring which line is which, Get back on here with us.

There are at least a dozen regular guys in this forum that can tell you all the info that I have.

Enjoy,

Jim

There are two fuel line nipples, I have found out a lot of info from this group. Are the Zama's any good? I hear so much about the Walbro, I don't know if I should just get a rebuild kit for the Zama or get a new Walbro.

The Zama can actually be just a good as the Walbro.

It's just that people in the past had a harder time cross referencing the Zama.

A lot of this has to do with the little number cast into the venturi of the Walbro ie "20", "28" which helped people readily identify sizes of carbs.

Whatever you do with your carb, you are going to need both a high speed and a low speed adjustable needle valve to use the engine on an airplane.

With the Ryobi engine, a choke is a good idea but not so important on piston ported engines mounted without a cowl.

Enjoy,

Jim

I agree with Jim. Save some money and time. Buy an 11mm carb. Use the money you saved by not kitting the too small carb to buy some refreshment for when you install the new carb.

Seeing how the engine was free, I will just look for a new carb. The engine will be going on the Great Planes Big Stick 1.20. No cowl.
Thanks again for the info, parts numbers and help.
Bob

OK, one more question,, would a WT-644 or WT-257 both with a 12.7mm venturi be too big? Should I stick with a 11mm one?
Thanks again. Bob

I would stick with 11mm. Quite a selection listed.

http://www.rcuniverse.com/forum/m_3810026/tm.htm

As Mike said, with the carb bigger than 11mm, the carb makes a bunch of noise and the engine doesn't run any faster. Throttle response is not as good.

Enjoy,

Jim

Got home from work last night, and checked out Ebay, and got a new in box Walbro WA55-1 for $28 shipped. 11mm. checked it out on Walbro.com and they charge $48 for one. Feel pretty good about that deal. Now for the motor mount, build a test stand and get this thing running. Thanks for all the help, I know where to go if I have more questions. Hopefully not too soon!