It is summer. In Florida, that means a lot of sweat and many nasty weekends spent mowing and trimming the lawn. What, you thought all we were doing here was going to Disney World? If 2-cycle trimmers are the cat's meow, then 4-cycle trimmers must be better, right? I mean, they still have two, don't they? Well, the Ryobi 4-cycle trimmer offers something that its 2-cycle trimmers don't. First, the reduced noise output at idle significantly reduces ear fatigue when you're away from a hard-working motor for extended periods of time. Second, the 30cc engine is more powerful than most, which means you won't get bogged down in thick grass…which won't be as thick if you're not that lazy and get out and mow a lot – but I digress. The last thing a 4 stroke engine offers is separated gas and oil (engine lube). This means that pre-mixed fuel is no longer required.
The Ryobi 4 Cycle Trimmer RY34440 promises, among other things, quieter operation and better fuel efficiency. It's a "green" product (more than one) and really cuts down on hassle when filling up because you don't need to pre-mix oil and gas. It also works with Ryobi's Expand-it line of accessories – they're even backward compatible with products I bought over 10 years ago. The 4-cycle Straight Trimmer only comes with a cord trimmer attachment, but includes both a raised head and a professional-style head for easy cord changes, and can handle larger diameter cords (from 0.095 to 0.105 inches). Using larger diameter strings will make your job easier, and we highly recommend choosing the largest strings that fit the Line In Pro Cut II string heads.
Editor's note: Check out our best gas line trimmers article for our top recommendations.
Ryobi 4 Cycle Trimmer Build Quality
The Ryobi 4 Cycle Trimmer is a great looking product. We love the new green styling. It reminds us of the plastic panels on cool motocross bikes. The system is available as a straight or curved shaft. We prefer the straight one because it's better for taller people and helps with under-deck cutting and other tight strides. The system works with Ryobi's Expand-It system, a single 4-stroke body can be used with multiple attachments. Currently, the company has 7 add-ons available:
- Edger (RY15518)
- Pruning shears (RY15520)
- Cultivator (RY15550)
- Brush cutter (RY15702)
- Hedge Trimmer (RY15703)
The Extended Reach Trimmer Attachment (RY15522) is almost identical to the one that comes with the 4 Cycle Straight Shaft Trimmer (except its shaft is yellow to match the Expand-It Series Trimmers). We actually used an old edger attachment from circa 1998 that fit perfectly on the axle and allowed us to trim the lawn after a quick weeding job. Accessory replacement is very easy and the process is completely tool-free. You simply turn the accessory knob to loosen it, depress the spring-loaded connector mechanism, and remove and replace the Expand-It accessory. It's so easy, even a caveman could do it…
The included Extended Reach Trimmer attachment has impact and pro tips. After many bump heads I've experienced, I see no reason not to quickly disassemble and remove the bump heads (by default) and replace them with better professional style heads. This took a full two minutes, and now I can buy bulk wire of thicker wire (up to 0.105 actually) and cut it to length as needed. Replacing the cord is as easy as securing each side length in place. You can even cut them a bit shorter, since the trimmer head contains a piece of metal that quickly disposes of any excess strands.
Looking at the motor, you'll see that the fuel tank has a capacity of just under a tenth of a gallon, oriented so that it can be refilled while the trimmer is sitting on the ground. The trimmer needs to be operated or even stored in this position to avoid oil leaking from the carburetor or muffler.
On the left, just above the radiator, you'll see the choke lever and starter bulb. The bulb appears to be well made and you'll want to replace this bulb after a few years due to the damage the fuel is doing to the synthetic. In front of the choke is the starter handle and rope, which you will undoubtedly be familiar with when using this tool. This is a half crank design with only one bearing on the crankshaft. Higher quality finishers tend to have the starter cord secured to the back of the unit so that it can utilize the full crankshaft supported by bearings on both sides.
Reviewer's Note: Please see our article on 2-Stroke vs. 4-Stroke Engines.
On the back of the trimmer, you'll find a recessed oil cap. The cap also acts as a dipstick to let you know the oil level. The trimmer should be checked by placing it level on the ground. Trimmer uses 10W-30 oil and holds 75mL of lubricant (oil) when filled. To check it simply clean the dipstick and then make sure the oil falls within the shaded area of the dipstick. It's important not to overfill, so be careful and use a funnel (a paper funnel is provided for the first use). We didn't find the unit leaking that much oil during use, provided we kept it level during storage. We did try hanging it vertically with the engine and blades facing up. Both develop leaks from the carburetor. So the only "safe" place to store this tool is horizontally on the ground, with the correct orientation. It's a shame because that takes up more space than hanging the engine face up on a double hitch (a two-stroke engine can be stored this way because the oil and gas are mixed and sealed inside the engine). The oil needs to be changed after every 25 hours of use.
Test Ryobi 4 Cycle Trimmer
Probably the biggest challenge when using this tool is launching it. That's a few more pulls than we're used to. Well, I'm being generous…you'll zap a dozen times before it starts. This isn't necessarily difficult in itself — it's just tedious. The starting sequence consists of verifying the choke setting, starting the bulb, and pulling the starter cord. Do not apply any gas to the throttle until the unit has been running for 6-10 seconds. This ensures you don't stall (or drown) the engine. We got used to starting the trimmer and after a while it seemed old to us, but it definitely used more power than any 2 cycle trimmer we've ever used. It's not a tool we'd recommend for most women or teens looking to mow their lawn.
Here are some interesting stats we've amassed over the course of a few weeks using the tool:
- Average number of pulls to start when cold: 10
- Average number of pulls started while warm: 1
- Average number of gears during use: 1 (mainly during idle periods)
- Average time for a single set of strings: will depend on your strings!
We've mowed a decent sized lawn several times with this tool and really got a feel for its weight and power. It's worth noting that the trimmer feels fairly lightweight, and the 30cc motor cuts tall grass with ease. It's a full 2 pounds heavier than our traditional Ryobi 2-cycle trimmer. We never felt the motor stall (not even once), and in fact had to keep reminding ourselves to "turn up the speed" during use because the trimmer was working just fine when the throttle wasn't even fully engaged. This is a powerful trimmer. We do experience trends that are prone to flooding. Flipping the choke into the wrong position while pulling the starter cord, overfilling the bulb or anything else can cause the trimmer to run at less than full capacity.
The Ryobi 4 Cycle Straight Trimmer has much more vibration than our reference 2 cycle trimmer. The added piston action and extra mechanics can really take a toll on your hands. Switching back and forth between 2 cycle and 4 cycle is like night and day, and we understand why 2 cycle may still be the go-to for most professionals and homeowners.
Noise output from the trimmer at idle is lower than anything we've heard from similar 2-stroke motors. We measured idle noise output 3 feet away at 80 db SPL. Compare this to our competition's 2-cycle measurement of 85 dB SPL (about 50% louder in terms of perception). At maximum throttle, the 4-cycle measured a SPL of 101dB, while our compatible 2-cycle (using the same strings and Extend-It attachment) measured a SPL of 102dB. We were disappointed to see the noise difference disappear once the accelerator was stepped on. As with any noisy tool – we recommend that you wear hearing protection if you will be using it for extended periods of time, or if this is your occupation.
We were impressed with many aspects of the Ryobi 4-Cycle Straight Trimmer. In fact, most of our problems were not the tools themselves, but the inherent limitations of the 4-cycle technology. If you care about the environment, the fuel efficiency and clean emissions of this Ryobi 4 cycle will stand out. The downsides are limited storage options (has to stay flat) and a more difficult start-up process, but that's no different than other 4-cycle trimmers. Treat them properly and they will provide years of continuous use. Luckily, Ryobi offers 2-cycle and 4-cycle products, so you have some options. We gave the Ryobi 4-Cycle Trimmer a 6/10 for performance because it packs a ton of power in a small form factor. The difficult starting process, vibration and tendency to leak oil when not fully upright left some room for improvement. We decided to compare this trimmer with other 4 cycle trimmers because Ryobi makes both. For value, we gave it a 7/10 because this trimmer offers slightly more power and features than many competing 4-cycle models for the price.