Small Engines (Lawn Mowers, etc.): Ryobi String Trimmer, ryobi string trimmer, armored cavalry regiment

Question
I have a Ryobi 725r, 31cc, 15" string trimmer, engine family is YN4XS.0314RA:EM.  This tool has not been run in about 3 years and I am trying to  get it working again.  It is not brokern simply been lying unused in my garage. Any suggestions on how or even if I can clean the carburetor and get it running again?  Thanks and I am also a Viet Nam Vet, 1967-68 11thc Armored Cavalry Regiment.  Hope to hear from you

Regards,

Bill

Answer
First of all WELCOME HOME BROTHER it has been long over due.

Now to your question Since this has been sitting around the gas/oil has evaporated and the carb is probably gunked up.

Carefully remove each part of the carburetor and take special note of exactly how each part came off or in the case of part assemblies, exactly how the assembly came apart.

Take special note in which order each part or assembly came off and or came apart. Note which side or which direction each part currently is facing or installed, prior to removal and or disassembly.

IMPORTANT TIPS:
It is highly recommend to only disassemble carburetors on a well lighted, clean and completely cleared off work bench. Carburetor parts are usually tiny, often freely fall out of removed parts or assemblies and can become easily lost.

Using scribe marks on metal parts or assemblies of parts will help to replace the parts in the location each part was installed prior to disassembly.

DIAPHRAGM CARBURETOR NOTE:
On diaphragm carburetors, look for a small hole in the carburetors engine facing side. This hole is bored into the body of the carb around the mounting surface.

On the engine mounting surface is another hole which goes down into the engines crankcase.This hole provides both vacuum and pressure, which must be allowed to enter into the carburetor.

Both holes provide a path for engine crackcase vacuum and pressure to act upon the diaphragm, causing it to fluctuate. The diaphragms fluctuations allows fuel to flow into the carburetor. Be sure both holes are cleared.

TIPS:
During the carb cleaning process, use canned aerosol automotive carb spray cleaner. Use it to clean the carb body, fuel ports, jets and airway passages.

The plastic extension tube, that comes with the canned cleaner, is an excellent tool to flush out sludge and debris from the jets, ports, fuel channels, airway passages, under welch plugs without removing the plug caps.

CAUTIONARY NOTE:
Use EXTREME CAUTION with canned aerosol automotive parts cleaner products. Aerosol cleaners are EXTREMELYFLAMMABLE!
Read the manufacturers product warning label.

SPECIAL NOTES REGARDING 2 CYCLE ENGINES:
Check for a fuel filter inside the bottom of the fuel tank or installed inline with the fuel hose. Some two cycle engines may have a weighted fuel filter attached to the fuel hose end inside the fuel tank.

The filter and weight combo should be able to freely move around inside the tank. The purpose of the weighted filter is to allow fuel to be drawn up when the engine is operating at angles.


Adjusting the carburetor on a 2 stroke engine
This is generic advice but probably a good place to start. It assumes that there are 2 adjusting screws - idle and high speed mixture.


I would start with them both backed out from the closed position to 2 turns open, for starters. One should be idle mix and the other should be high speed. Crank the motor, get it warmed up. You may have to fiddle with the throttle and or choke until its warmed up. Then slowly turn in the low speed jet, until it starts to die, then back it out another 1/4 to 1/2 turn. Then hold the throttle wide open, and slowly turn in the high speed, until it really starts to smooth out and rev high, and start screaming, then back this out until it starts to run rough or slow down, and then turn it back in to midway between these two positions. Keep playing with the low speed needle until you get rapid immediate response from the throttle, and good idle with the idle adjustment. Then play with the high speed needle, but always back it out from the setting about 1/4 turn or so, from where it runs the smoothest. This setting of backing it out will allow more fuel when under a load, and keep your 2 cycle motor from running too lean. Put a load on it and just tweak the settings just a hair at a time. If you're in the ball park it won't take much adjustment either way to make a difference. Better on the rich side than lean side. Also make sure your oil / gas is mixed at the proper ratio. 99% of 2 cycle motors are adjusted the same, no mater what brand they are. Most will start and run with both screws open 2 turns initially. Just don't close the high speed off any more than necessary no matter how well it runs.