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Posted: 5/8/2004 3:43:13 PM EST
I have been keeping an eye out for a weedeater at garage sales and found one today. The guy I bought it from seemed knowledgeable but he couldn't get it running so he had given up and bought another one.

This particular one was a Troy-Bilt, and instead of being a complete unit, is designed as a motor and shaft to which you can attach various accessories and seemed way cool. Well, I futzed with it and then tore it down. When I exposed the magneto coil I saw something on it that almost made me give up right there-Ryobi printed on it large as life. I decided to keep going and observed that the valve lifters were functioning about ten percent of the time when you spun the crank. Rotating it backwards the valves worked normally.

The lifter assembly was composed of a cam gear and follower/pushrod assembly which swing on two shafts at either end of a small bracket held in place by two cap screws-which were loose. Totally bogus, but an easy fix. But after playing with some more, I noticed that the cam wasn't spinning as much as the shaft. Then I found that the drive gear was spinning around the crankshaft.

Not all of you are familiar with small engine design so I'll explain my beef in detail.

These little engines are usually two cycle. The advantage is that you get more power out of less weight. But, since they breathe through the crankcase you have to mix the oil into the fuel which often means they don't last as long and are more poluting.

This particular engine however is four cycle, the smallest one I have ever seen. The oil lives in the crankcase, it breathes though valves at the top of the cylinder and the cam which forces the valves to open has to spin at 1/2 the speed of the crankshaft, hence the gear.

This brings me to the design flaws in this engine.

First, small engines have a flywheel (weight-inertia) which often serves also as a cooling fan (fins )and magneto (a magnet in the rim excites a coil which provides a jolt of electricity to the spark plug). Being heavy, it can damage the engine if the engine were to stop suddenly if say, your lawnmower blade were to strike a rock or board etc. The flywheel has to be indexed precisely but also able to break free of the shaft in the case of such a sudden stop. A shear key will break allowing the flywheel to spin on the shaft instead of damaging the engine but must be replaced before it will run again.

This engine, instead of a shear key, has the index cast into the flywheel itself. Granted, a tiny engine on the end of a long shaft like this will not likely come to a sudden enough stop to cause damage but if it did, you would have to replace the entire flywheel-and would probably not be worth it.

Second, the gear which drives the cam has no such concerns and should be keyed or splined securely to the crankshaft. That in normal use it will come loose is inexcusable. In order to repair this I'd have to remove the crankshaft which seems to have pressed in bearings. I'd probably destroy the engine trying so it's the end of the line for this little piece of crap.

And this is just another example of why some us of hate Ryobi so much. Thanks for reading.
Link Posted: 5/8/2004 3:51:03 PM EST
The unit is cheap, it is designed as a throw away. Most small engine shops I am familiar with have labor rates in the $55.00-75.00 an hour range. How much are you willing to pay to repair something that costs little more than an hours labor to repair.
Link Posted: 5/8/2004 3:52:10 PM EST
All I know is mine is from Sears, and has a Tekumsa (sp) engine. I had to put a new belt in it last week though.

Digital
Link Posted: 5/8/2004 3:52:59 PM EST
Link Posted: 5/8/2004 4:05:37 PM EST
Well thanks for the insight on small gasoline engines. That is one thing I don't know too much about.
Link Posted: 5/8/2004 4:25:45 PM EST
I own around half a dozen Ryobi power tools, and they have been absolutely bulletproof. Great product for the money, IMO.
Link Posted: 5/8/2004 5:01:34 PM EST
from the grapevine:
the Ryobi "disposable" weedeater 2 stroke and the accessories will be gone soon. Ryobi is forcing (because of air regulations and The People's Republic of Kalifornistan) 4 cycle and the accessories will not fit ON PURPOSE.
Link Posted: 5/8/2004 5:03:29 PM EST
[Last Edit: 5/8/2004 5:04:18 PM EST by laynlow40]
My Ryobi lost compression during its second season. I have also had a couple Craftsman trimmers. I finally decided to buy a Honda 4 stroke and have never looked back. Its quiet, has a solid shaft drive with ball bearings, and starts on the first pull. I think I have had it three years now.

I don't by consumer tools anymore. They just don't hold up. My blower is a Stihl backpack .
Link Posted: 5/8/2004 5:22:19 PM EST
Link Posted: 5/8/2004 5:26:38 PM EST
I just picked up a Honda GX31 engine, was considering a Ryobi for a minibike project.. Glad I got the Honda now.

Dave
Link Posted: 5/9/2004 4:03:45 AM EST

Originally Posted By Skibane:
I own around half a dozen Ryobi power tools, and they have been absolutely bulletproof. Great product for the money, IMO.



Yeap, I got a 5" circular saw, a saws all, a chainsaw, a flashlight, drill, and Jigsaw with two 18v battery pack all for just $220.

I have dropped them, kicked them, ran them till the blade was smokeing, and the fuckers still work great!!

Ryobi makes lots of power tools for lots of people. I believe even some craftmans tools are made by them.

Very happy with Ryobi, and I like the blue color.

SGtar15
Link Posted: 5/9/2004 4:36:26 AM EST
i have had a ryobi one for about 4 years. paid 65.00 for it. no problems at all. My yard is pretty tough on yard tools and i only expected to get 2-3 years out of it.

mike
Link Posted: 5/9/2004 4:43:38 AM EST
Ryobi string trimmer here for about 4 years now. Used every week spring through fall, great little booger so far.
Link Posted: 5/9/2004 4:45:48 AM EST
There is a difference between Ryobi "power tools (electric)" and their gasoline powered stuff. The gas stuff is throw away.
Link Posted: 5/9/2004 4:47:08 AM EST
[Last Edit: 5/9/2004 4:47:52 AM EST by 6731HBAR]
I just bought a Ryobi trimmer last weekend. I like tools but I hate spending money on this type of stuff. Money is made for three things: 1) Guns/gun Accessories - usually AR's, but others will work. 2) Motorcycles- and accessories 3) Food, yeah I know if you have guns you can take some else's food. But they might not have exactly what you want, and considering how most people cook today, it will probably be burned, out of a box, or have bugs in it.
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