I had the same thing happen to me a couple years ago on a different hand held. I just about reached for the tools when I decided I wasn't employed by the factory and their quality control wasn't my job. I didn't break it down and re-box it, just took it back like it was.

I purchased a Ryobi S430 on the 31st of March from Home Depot and I had the same issue. I returned the trimmer this morning and exchanged it for another one. When I spoke with the power tools "expert" at Home Depot this morning and he suggested that I should not prime the engine 7 times as indicated and only prime it until I see fuel in the bulb. I did just that and still have the same issue. There must be some design issue with the throttle/choke. I can manually hold the start/run level half way and the engine will run at full throttle.

Here's the end of the s430 saga. I took the new one that wouldn't run at full throttle without dying back to Home Depot and exchanged it for another s430. Got it home, when it started up it was misfiring when I first started it after assembly. After about 5 mins the misfire went away. I used it for about an hour and then crankcase oil started leaking out of the air filter (quite a lot) and the misfire came back. The replacement would run at full throttle but developed a misfire which was more like a hiccup where the engine stopped and then immediately fired again. This was quite uncomfortable as it rotates the trimmer in my hand when it refires again.
So off I went back to Home Depot, and got a refund. Ryobi, if you read these forums about your products, go back to the drawing board with the s430 as they're junk.
I went off to Lowe's and bought a Troy Bilt 4 Cycle. It has about 1cc less on the engine and 1" less on the cutting swatch but most importantly it works.

I would strongly recommend against buying the current Roybi s430 model and that probably goes for the c430 model too since they both have the same motor.

LR

I tied a small electric strap around the choke so it won't close all the way. Works like a champ. My 875R had the same issue but you could adjust the choke manually. Lasted 10 years. Thought I might try a foam filter under the plastic cover. Not sure about that one

My S430 has oil sputtering from the PCV(?) tube that is located within the same black plastic housing as the carburetor air intake causing oil leaks from under the housing. The carburetor air intake also sucks up some of the oil causing misfires, and smoke from the exhaust. Anyone else have this problem or a solution? The crankcase oil level is okay and not overfilled.

Similar experience with the C430. Dies at full throttle. Took it to a local person for repair. He told me the C430 was junk; no air filter, no choke adjustment and leaks like a sieve. Very disappointed in Ryobi; bought this trimmer based on success of power hand tools. Will replace it with Stihl or Echo.

I have the same problem only a year latter I suspose my lost but I will never buy another one from Home Depot.

Docdavid, please post more details for adjusting the the carbs on the Ryobi c430 trimmer. Thanks!

OK, here are some of the particulars: First let me say that I still haven't figured out why these trimmers don't have an actual air filter. Maybe more on that later.

Second, to adjust the carb, you must first acquire the proper tool. I found my set of carb tools on ebay from the vendor: Randy's Engine Repair. I got a set of four, but you could order just the one you desire. (No connection with this vendor, other than a very satisfied customer) You'll need the "pac man" tool to fit the Ryobi carb adjustment screws.

The instructions below assume that you have a functional carb and an engine that has compression and spark. Fresh clean gasoline, no broken fuel lines, etc.

Tool in hand, remove the carb intake cover. The high and low adjustment needle screws are viewed looking at the carb from the shaft end of the motor. They are round and black. Fit the tool over the spline of one of the needle screws and turn in the screw clockwise until seated. Be gentle--just finger pressure. Now turn out the needle one and one half turn. Do the same to the other screw. Now you have a starting place.

Parenthetically, here is where small engines differ profoundly from the computer controlled engines we generally use, like those now found in cars. In small engines. purely mechanical settings control air/fuel ratio. The owner of said small engine has to take control to achieve the proper air/fuel ratio. It's stoichiometry!..

But back to the trimmer.....

Leaving the air intake cover off,

Start the trimmer (using the choke lever and starting instructions as noted on the start label). Here is where the art work begins. You are going for a well running engine that idles well, and has full power when working under full throttle. You will need to experiment with carb settings. One of the needle screws influences idle performance mainly, and the other is mainly for full throttle performance. However each jet influences the other. Engine running, at idle, adjust the low rpm jet to slightly lean (turn clockwise until you hear loss of rpm) then back out the screw a bit, say one quarter turn. Now test full throttle. Squeeze the throttle control. If the engine dies (the main problem with these trimmers) it is still probably too lean so open (counter clockwise) the H needle one quarter turn. Try again. Etc. Adjust the high speed needle for good performance. Basically you are trying for highest rpm, but a bit richer, say one quarter turn counter clockwise.

To find out which screw is idle or full throttle, do some experimentation. When you get the motor to idle, just fiddle with one needle, then the other. By fiddle I mean slowly open or close the needle. The one that causes the most immediate changes in the idle rpm is the L or low speed jet, and the other is the H or high speed jet.

At some point I may get my lazy back side out to the garage and make some videos of this kind of stuff and post them on youtube.

I hope this is helpful to those struggling with these trimmer motors. The above principles apply to four and two stroke engines. The basic problem is that emissions regulations force the manufacturers to adjust the air/fuel ratio very lean, which leads to poor running and, in the case of many engines, high temperature running and engine seizure. And then you have the issues with higher and higher ethanol content in fuel.

Let me know if this is helpful. Or any other questions on these little trimmers.

same here! Should have went with a 2 stroke. I cant even get it started now

Hi Does anyone know where I can find the sprocket that attaches the timing belt?

This is for the ryobi c430

http://www2.snapfish.com/snapfish/viewsharedphoto/p=8451307329237207/l=13768981007/g=79168894/cobrandOid=1000/campaignName=ShareeNewReg_30FreePrints_2010Feb/otsc=SHR/otsi=SPIClink

In response to willyk's post about the oil leak. I am having the exact issue. I drained the oil and refilled with Ryobi oil but problem persists.

Oil is not overfilled. Unit has less than 5 hours of total use in the last year.

Can't believe this problem continues with what seems like zero concern by Ryobi.
I did find that if I make sure the gas cap vent is cleaned before every use the problem seems to be cleared.
Good luck.

Maybe it is Ryobi's method of keeping under the air pollution limits! After all--a non-running engine doesn't pollute! And a low revving engine pollutes much less than a fast runner! Simple explanation, eh? It is a wonder none of the other gurus here had thought of that!

docdavidb is on the money. I had the same problem, bought the tool, followed the instructions exactly. Within 5 minutes, this thing is purring like a kitten. While it's a shame that these things aren't properly adjusted from the factory, they're great now!

I will second that! I purchased a refurb S430 and have been suffering with poor performance for about a year. After reading this post, I made the carb adjustment and it runs great!

Couple of notes for the less mechanically inclined:
1. The carb intake cover is the piece of plastic with the run/start instructions printed on it. It will pop off with no tools required.
2. The High/Low adjustments are labeled- if you looks very closely you can see 'L' and 'H'.

Thanks for the tip docdavidb!

Hello, I'm glad to see this problem is still current. Well, not glad but it does help since I just got a C430 with the same symptoms. I'll post photos after I finish the disassembly but I think the needle adjustments may be all I need, so far it is spotless internally.
jim

OK, thanks to help from here and elsewhere on the web, I now have a functioning Ryobi. The link is the photos I took during the adjustment. I'm too cheap to buy the special tool so I just cut slots in the screw heads.

One other tip I found. Once you set the choke lever, you can open it slightly and still have the throttle set on the fast idle speed cam. Don't know if this was intentional from Ryobi as it's not listed in the instructions. It helps when restarting a warm engine.

Here is a link that might be useful: Ryobi carb adjustments

Sorry to bring up an old thread, but I was just given a c430 (curved shaft version) with some attachments. I'm a new home owner and cash is tight. My friend said the carb was bad, so took it apart and rebuilt the carb.

I cleaned the lines and changed the plug.

This will start and idle fine choked. Will purr like a kitten when the throttle is pulled, but as soon as the throttle is let go it dies. I put the choke on and it starts right back. Pull the throttle and away she goes. Let go and it dies.

I've tried adjusting the carb to no avail.

I've pulled the muffler and cleaned it as well.

Any other suggestion on how to get this thing to run with choke open.

Thanks in advance

I am not having the engine die at full throttle yet, but what I have encountered is: the other day I went to pull the string to start and noticed I was not turning the engine to start it. I removed the shrouds to access and noticed the drive belt had slipped off the upper crank, I reinstalled the belt and tried to pull again, after 2 or 3 pulls the belt has slipped off again-repeatedly. I have opened the unit up completely to try and find some type of tensioner for the belt but cannot-has anyone encountered this problem or can anyone assist. Thanks

I had the same problem of lost power at full throttle after the engine is run-in for a few hours. It was a pain (and expense) to try to get the pacman tool and my carb seems to have only one pacman screw head. Also, I am using the tool on a small island where bush-mechanics applies. I found by losing the warranty, I could make a thin hacksaw cut across the top of the screw (see photo showing 1/4 turn open) and adjust it with a regular small screwdriver.

OK, now I read through all the postings and saw someone else already had the idea of saw-cuts in the screw heads to bypass the special adjustment tool. From the photo in that posting, my unit has a different carburetor as it only has one adjustment screw. Perhaps it is the "Canada" model?

you should probably have a certified tec take a look at it with the proper tools, trying to adjust the carb you self could in up in a lean seize which is not warranty, or running way to rich, with cause excessive carbon build up, also if you cut the slot wrong and can not get a tool on the adjustment, your screwed and need a new carb, plus most likey it has a ruining carb wich has no internal parts availabe but if yoju know so who has experiece with zama carb they can find you a kit but finding someone who is willing to help you is a different story

I am new here, but wanted to post my results. docdavidb is correct in his posting on fine tuning the carb. As far as cutting the needle/screw heads, the carb block is aluminum and the needles are brass, so no worries for sparks above the gas tank. i used a dremel w/ a metal disk, it notches the alum. good for referrence points and gives the heads access w/ a slotted driver. Tuning the carb is much like a 4wheeler or and old VW, yep showing my age.One thing not mentioned is the idle adjustment screw, the larger silver screw w/ the cone shaped end, above the carb. I backed this out until the plate attached to the trigger cable was no longer touching, pulled the trigger and let it snap back. Then I turned it back in until it just touched the plate, and then adjusted in and out, about 2 and 1/4 turns, produced a good idle for me That being said, 1 and 1/2 turns for the high/low screws is a good starting point. Low is on the the left as you look up the shaft to the engine, high on the right. I ended up with about 3 turns out, from seated all the way in on the low, and about 1 and 3/4 turns on the high. I cut my trimmer line for testing, but after it was running well, I extended the line. I tested in heavy brush and it bogged a bit, so i turned the high screw in 1/4 turn. Much better. One note of advice, as we move away from things that are actually adjustable, and we can't even work on or own tool anymore... If you come across screws, needle valves etc, after you've turned them all the way in, make a mark, and as you back it out, repeat this mantra as you turn, 1/2 then 1... 1/2 then 2...1/2 then 3...etc. This is why all needle valves/ screws were origionally slotted. Make notes, if you adjust 1/4 or 1/8 turns in or out, if you ever have to completely disassemble a carb, it is a good starting point. I will post a pict of my carb if I can get a heads up on how in this forum. Good Luck.

This post was edited by sranke on Thu, Jul 18, 13 at 21:17

Well today, after reading this forum. I took out my one year old c430 and decided to get the dremmel after it. I carefully cut a slot into the top of the adjuster, being careful to not cut too deep into the carb housing. I used the thin grinding/cutting disk. Now a regular screwdriver turns it just fine for free. No need to buy some extra tool. Now I have it adjusted and it runs rather well. I seem to have the same carb as radio does.

I bought a 2011 c430 that would not keep running.
Replaced spark plug which was found finger- tight.
Changed the oil.
Replaced the fuel lines and filter.
Adjusted the lifters (metal cam shaft)
Dremmeled the carb screw slot.
Adjusted the only carb mix screw. Tightened all torx screws.
The valve cover and oil pan screws were all loose.
Now it starts on the first pull and doesn't smoke at all.
Not bad for $10!

Next day, ran through 3 tanks of gas. Cold start after 3 pulls and only one pull when warm.

This post was edited by tonyski on Sat, May 24, 14 at 17:54

losrubios: (C430 spits out oil) my mom bought a sears (rebranded Ryobi 4cycle) it had many problems all around burning, leaking oil. (after problem 4, she got her money back) so losrubios, you are not alone.

I went to a sears repair site to get a fridge water filter and noticed they had 6 of them hanging on the wall - refurbished for sale.
That model obviously was a lemon.

Radio I borrowed your photo to show as an example.

Ryobi uses what is known as a Pac-Man screws for carb adjustments. Other types from different brands of power equipment include Single D, Double D, Spline and D Spline.

Dealer are not "legally" allowed to sell carb adjusting tools to the public. I was able to pick up a complete set years ago for around $10.00 before the ban kicked in. You can still find them for sell on the web but they fetch a good penny now days. But you can get them.

I have ground slots into older equipment to adjust the carb. But when it comes to something under warranty I use the proper tools. For if you take something in for warranty work or exchange and they spot that the carb adjustment screws have been "hacked" they can refuse to replace or honor any warranty on the machine.

This post was edited by hippy on Tue, May 27, 14 at 17:58

After 5 tanks of gas it still starts on the second pull, but now it seems to be bound up somehow. While running it just slowed down and came to a stop. starts fine but something is preventing it from running

The lifter post came loose. Tightened it back down, adjusted lifter and all is well.

From the manual...While holding a wrench on the flats of the adjusting nut with one hand, loosen the retaining nut with a second wrench as shown. Take care not to loosen the stud.

This post was edited by tonyski on Mon, Jun 2, 14 at 14:59

Mine was running so erratically till I read this thread. I loosened the air intake/filter housing and used my dremel to cut a slot in the carb screw turned it a quarter of a turn and after tightening it all up "boom" it starts first pull and keeps going.
Thanks for the help it was driving me mad

The post docdavidb put out there really helped me with adjusting the carb. But the trouble I continue to have is I can only keep full throttle if I take the filter out. I've tried cleaning but as soon as I put filter back in I only get about 3/4 throttle. Any ideas?

Does any body has a problem with this trimmer that runs OK but the motor will not engage the metal cam shaft so the lower part will not run?

Sounds like a bad cable or clutch if I am reading this correct. Have you disassembled and what did you find? A bad cable or bad clutch matters are usually obvious due to broken parts disassembled. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Throttle...

I have had this thing for a few years now. It had always been a pain to get going. But once warmed up would work well enough to get the job done. (You get what you pay for I always figured) This year, not so much. Made adjustments to idle screws (L) 1/8 turn out, (H) 3/4 turn out, and played around with the Large cone tipped screw mentioned above by sranke. Runs very smooth now. Still need to let it warm up a bit, but smooth. Thank you docdavidb

Hippy - the tools are still available on eBay (from the Orient). They run about $7 ea. or a set of all four for $20. Free shipping, but it might take 3 weeks for the boat to get here.

I have an s430 that runs very well but after turning it off to refuel, it seems there is too much compression; can't pull the starter until I remove plug and release compression and put plug back. Is there a vent I should check or...?

To any of you fellers who have to separate the parts of the engine, upper and lower halves, do not use "Blue Goo" when reassembling the halves. Use the regular paper gasket! This maintains proper settings on engine internal engine parts, and prevents possible engine failure at some future time!

I had the problem with 4-cycle 430. It would idle okay, but died when it went went high RPMs. I drained MOST of the gasoline out of the tank and sprayed carb. cleaner directly into the gas tank ( about 3 - 4 seconds). I started the engine and let it idle with choke on, then half choke, and finally no choke after about 15 sec. of idle. I slowly increased the speed until it ran at full rpm's for a few minutes. I filled the tank up leaving a little gasoline (with remaining carb. cleaner) in the tank. I ran through the full tank blowing leaves. I refilled that tank again with no carb. cleaner and it still works fine at high RPMs.

Time will tell...

I would like to know how to adjust the valves on a RYOBI S430 string trimmer, wish someone would make a video on how to do it. By the way thanks for all the information, it has been very helpful.

I've suffered with an S430 in California for awhile. I noticed above that there is mentioned of a L and H adjustment screw on the c430. On mine, I can find only one on top, nondjustable until you Dremel it. What does it adjust?

I guess Ryobi has been following this string of what appears to be good advise. I just bought a new RY4CSS, apparently the newer model, ran it for about an hour, then started having the same problem you all had: engine dies at full throttle. However, I don't see any of the adjusting screws, "PAC-man" or otherwise, anywhere on the carburetor. The only screws I can find just hold parts together, or hold the carburetor to the motor. I can send pics if someone is familiar with the newer models. Wish I'd seen this site before I bought this trimmer.

I also have RyobiS430 that does not have H/L adjustments on the carb as pictured in other responders. Have you found a solution? Do I have to replace the Carb with an older Carb that does have the packman adjustment screws.

I am working on a newer unit that has no carb adjustment screws. Seems Ryobi decided to not let the user fix the problem. I replaced all gaskets in carb, new lines, no clog in the muff.....WTH? How is a person supposed to tune their owned equipment? Only people with the right tools or know-how will attempt an adjustment. I don't understand why they would take the carb adjustment screws away!

I bought one and it has run great, the only time it sputters is when the cutting line is getting short. I tap the head get more line to feed out and the sputter is gone. My spec sheet calls for 20w-50 oil. My experiance with most chinese made gas motors (which is probably most that we find available these days) is that they test run them at the factories then ship them leaving some gas in the fuel system, and since from test run, shipping, to sale is usually several months this allows the fuel system and residual gas in it to lacquer up. On anew purchase I usually put some rubbing alchohol in the fuel tank, then take the spark plug out, prime the fuel system, pull the start cord till I smell rubbing alchohol coming out of the spark plug hole. Then I let it sit a day so, the rubbing alchohol dissolves the lacquer, then I put gas in and start it up. I never have problems using this procedure. If you have lacquer gumming up your jets you can adjust the carb all you want but it will never run right!!

Yep , you are spot on rb , good advice !

Markwys Where did you get a gasket kit? I see a new carb can be purchased, but not a kit.

The newer ones use a Ruixing carburetor, which has no crossover. There is a pack man high speed jet. You may not see a idle jet, but bringing the stop screw up a little actually adjusts the idle needle. Shame Walbro has a adjustment for the jet lift.

These are a bear to start, but you need to follow the instructions, The diaphragm and the diaphragm gaskets are special, Setting the needle requires a Walbro or Zama tool because it has a deep float well.

Lots of Viton and EPDM gasket sets available @ premium gasket distributors . However not cheap $12 to $14 bucks a set , compared to offshore $3 to $5 sets . Epa carbs , and throw away offshore engines are common @ box stores these days unfortunately .

My brand new Ryobi S430 has the same problem. How did it ever receive a 5 Star ? No More RyobiRyobisRyobisRyobiRyobi.

If you have any problems with a Ryobi after a few years, the easiest thing to do is to buy a new carburetor kit for $16 on Amazon. My S430 kit came with fuel lines, fuel filter, carb with regular slotted adjustment screws, spark plug, and two extra bulbs and extra gaskets. Replace everything, adjust as mentioned above and Voila!! My old carb had one hidden PacMan screw under a plastic cover, but there was an internal problem with the carb. You can spend a lot of time chasing down one problem after another or just replace it all for about the same price as buying gaskets to rebuild the carb. Also, 4-stroke Ryobi is notorious for leaking oil through the crankcase breather valves into the air filter housing if you don't store the power head level. Never hang it vertically. Replacing these two valves is a good idea as well. Look like little white filters that connect through tubes to the cylinder head. Release air pressure from piston moving up and down. One-way valves.