Hi,

I just pulled this Ryobi out of a Turf Power Model 720TP weed wacker. Can anybody tell me what size it is??? I know it's smaller than my Homey 25, I'm guessing a 15 cc???? I've found the parts breakdown on the net but I can't seem to find anything on it's size.

Chris

It looks just like my two 31cc Roybis that I salvaged from a pair of weedwackers that I paid $10 for.

It looks to be the long shaft ryobi 31cc....
i have the short shaft out of a yardmachines 2800M and it looks like this: (after the conversion process)
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Ryobi only makes either a 30 CC (newer models) or 31 cc.

i thought they had a 28ish cc engine as well.......maybe in a fourstroke?

Thanks guys,

I'm new to this week wacker engine conversion stuff. I'd swear this thing looks smaller than my 25cc Homelite!

Chris

homelites tend to be a bit "bulkier" than the ryobi. thats why some people like the ryobi, because its very narrow (due to carb and muffler behind engine) which allows them to fit into cowls easier. for power, i would pick the homelite over the ryobi any day.

That looks like a Ryobi 28cc. It was the predecessor to the 31cc and you can tell the difference between the two because on the 28cc the front metal flange was bolted on rather than being a part of the crank casing. I see that's been removed in your photos. I remember the 28cc because it was the first engine that pulled out of a strimmer and I still have it somewhere.

Second question,

Where can i get a muffler for this engine?? Carr's???

Chris

The 28cc Ryobi has a slightly different cylinder fin configuration at the spark plug. The 31's have a full top fin as in your pictures and the 28's a couple narrow fins at the plug. Somewhere I have pictures of this and if needed will gladly post. Other than the fins the two are for the most part identical..............Bob

A long time ago, I asked how to tell the 28 from the 31, and I was told the only way to really know is to pop the cylinder and measure the piston diameter. I'd love to know if the fin thing is correct, or some other easy way of identification.

Bill

I've just looked at my 28 and 31 Ryobi's side by side. The 28cc has the earlier fins as described by Bob above and the earlier crankcase as described by me. The 31cc has the later fins and the later crankcase. I have no information on the order in which the changes were made during production and whether they were in any way synchronized with the change from 28cc to 31cc. So if one really did want to know whether it was a 28 or 31cc then measuring probably is the only way.

As for the muffler, either Carr Precision or Wacker engines can supply. They also supply all the other parts needed to convert.

Maninder.

Well it's pouring rain here so with nothing much else to do I went to the barn and took a couple pictures of the 28cc cylinder for you. They are completely interchangeable with the 31's as are their crankcases. The one piece crankcase is a much later version and only 31cc engines were made at that time. The earlier style crankcase's are stepped towards the front and take a slightly different and smaller dia. reed housing and back plate. Also the crank itself has a slightly smaller counterweight dia. as the inside of the case is more compact than the next version. Next comes the unstepped crankcase with the later style reed houseing/back plate. It has a little larger inside dia. and it's crank won't go into the stepped case but it's piston and rod will, though the earlier piston cannot be used on this crank as the notch in the skirt isn't quite large enough. The 3rd. version of this engine comes with a one piece crankcase and flywheel housing and it's internals are the same as the second. How's that for a rainy day lesson? Now don't get me started on the Stihl FS 36 and 44's which are also Ryobi's but with some other changes........Images too come as I try and get a bit smarter......Bob

Well, hopefully Here They Are..........

Yep - that looks just like my 28cc.

Given your knowledge of Ryobi engines, here's a question that's bothered my for a long time.

I can buy a 30cc Ryobi blower that uses the homelite engine over here for around £90. A ryobi blower with the 31cc costs around £165. The latter seems to be a more uparket unit. But why such a huge difference in price? Is the Ryobi 31cc engine really considered to be that much more upmarket that it's only installed in the more expensive units?

I know this is going off the subject of the original post a bit but hopefully others might be interested also.

Maninder.

Well Maninder that's an interesting question which in no way am I qualified to answer. However it dosen't stop me from having an opinion! So here goes; I think when you compare the 30cc Homelite based engine to the 31cc typical Ryobi you will find that the Homelite is better made in terms of bearing size, rod & crank construction and cylinder configuration. Therefore it seems that on the surface the 30cc Ryobi blower would be the better deal. But, there is an even later version of the 31cc Ryobi then was mentioned in my earlier post. While it looks kinda the same and does have the same rod, crankpin dia, and piston it is piston ported ( no reed) and turns clockwise. I have only seem them in blowers and both I have are in good shape internally though the blowers had stopped running for some reason. Also,There could be some other engines now under the Ryobi banner that are better designed and built the either of the versions we have been talking about. If it were me I would go for the cheaper one and then use the extra money for something more pleasurable then blowing leafs..............Bob