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Hi folks;

Can you tell me if the green machine #2840 by John Deere is produced by homelite ?. Is this a 28cc engine or a 26cc or even a 25cc. The number 26 is stamped on the block. This engine is I believe a short shaft one although it came with a clutch. The nut for the flywheel is recessed and to be honest I am not sure if the prop should go on the flywheel side or the pull start side. I have heard of prop hubs for these but again I am unsure if it is for this application. I have gone to rcfaq.com but did not see what I was looking for. Is there a place in Canada that sells prop hubs and other conversion accessories. You can tell this is my first conversion and I apologize for some of these greenhorn questions. Thanks. Peter

Weedie
 

How many bolts hold the cylinder to the block??

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Hi TKG;

4 bolts hold the cylinder to the block.

Weedie
 

Well based on 4 bolts and the PN. I'd say Mac 28cc.
Futher things is the muffler held on by a coil spring and a wire clamp. Rear cover plastic with 5 bolts.
Get the muffler off there should be the size cast into the cylinder under the muffler. White mag coil. Most important the flywheel and pull starter is on the same side. All the above is Mac
Any one thing is not then no idea what you have

More Weedwacker
 

Well.................. the muffler is held on by two bolts running straight through to the cyl. head. The pull start is on the opposite side of the magneto and fly wheel and is held on by three bolts. the flywheel housing/ clutch assembly is held on by four bolts and several alignment pins. ( the clutch itself being held on by two bolts) The engine is almost brand new since the bottom half of the weedie had a critical mishap. I don't know when it was purchased. I looked at Carr Engineering web page and it does not look like any of them, but resembles the homelite. Stripped without shaving any metal yet it weighs 3.2 lbs. It also has a plastic? spacer (1.25" thick) betweeb the carb ( that has no hi/lo mixture screws) and the cyl. head.

engine
 

Peter: Pull the recoil slow and see what direction the shaft turns. The end of the shaft that turns counterclock-wise is the end you will have to use for prop-adapter. Take off everthing you do not need ....figure how you want to mount it to firewall....make or have made a prop adapter. Place on test stand....see how she runs. Good luck capt,n P.S. If you got a scanner...post a photo

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Sorry I can't send any photo's. I found a few more numbers............. they probably still don't mean a thing. Model TL26PFD-T5H E/No. 187758 5K. I was wondering if a prop hub from a Zenoah 23/26 would fit or any other commercially produced adapter. (notice that darn number 26 pops up every where.) Thanks again.

SEARCH
 

Do a search on the World Wide Webb.....should be sites listing this engine. I would...but I gotta go away Cap :D

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Peter : Is it piston ported or reed valve. Most, but not all Homelites are reed valve.

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Thanks everyone for your help. I went to the local John Deere supplier/repair shop and the mechanic was positive it was a Ryobi 28cc. So what that number 26 is, is beyond me. I guess thats why it was called a Green Machine 2840.
Anyway, I am going to try and get a long nut to bolt onto the flywheel for the prop shaft (hub). I checked the rotation of the flywheel by installing the pull start and indeed the flywheel rotation is counter clockwise. The mechanic also say's he works over the ports and advances the timing on lots of chainsaws etc. and can guarantee to increase the horse power by a considerable margin. I will probably have him do that, but would like to tach it first, before the hop up. Thanks again and I will try and post some results later.

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Interesting though, I was just on the www.rcfaq.com page and it states that the Ryobi's have a rear exhaust. This one has side exhaust???????????????/. @***!/. Oh well who the hell cares (besides me) :-) . I'll get it going and tach it, see what it developes.

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The Ryobi that everyone refers to as a Ryobi on here is the 31.

There is a smaller 2 cycle one seen occasionally that I remember as being a 26 or 28 but I only saw a few and that was 3 or 4 yrs ago. They were made completely different from the 31.

There are also 2 different four cycle Ryobi's. They generally have such a poor power to weight ratio as to not be very attractive for model use.

Jim

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Thanks W8YE;

This being a 2 cycle. Is it the 4 cycle that was poor on power?. I even went to the John Deere web site and it is the M-series engine but damned if I know who makes it nor did they say. It sure is a pretty little thing :-) .

PHOTOS
 

Peter: You can purchacse a digital camera for web use real cheap. That way you can take photos of this engine and all the RC things you have. That way you can show what you have for sale or trade....OR.... You can also take photos with any camera and scan them for sending or viewing. You will need a scanner. I have seem them for $39. Anyway it would be of great help for doing this hobby. A picture is worth a thousand words. Captinjohn

engine??????
 

IS IT A REED VALVE ENGINE??????? question one over

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Hi Captinjohn;

Looks like a ported engine. Casing is made in Japan. Flywheel say's ikeda-d . (I wonder has that got anything to do with furniture :-) ) I got a cool prop hub machined today from a friend in a machine shop. He gave it to me for free but I insisted on giving him a few bucks. I have a MA. 16x6 I will try on it and see what rpm's I get. I hope to get 7000 rpm from it, but in truth I have no idea what a 28cc should get if it is a 28cc. The John Deere dealer said he could hop it up for me by re and re the ports and advancing the timing a bit.

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A 16 - 10 will be more like it.

Jim

engine
 

Hi Peter: How did you bolt this motor to your test stand? That may also be a clue to what this engine is. Thanks John

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I have not bolted it yet to the stand but it has a housing that looks like a wankle engine combustion chamber. Triangular in shape with outside curves between points. At the end of each point is a tapped hole. This is where the pull start was attached. In the center is a threaded 8mm shaft (crank). I will not need to make any engine mounts, just simply use the existing holes. You can see the bearing, so this engine has two bearings. That brings up another subject................ I don't want to push my luck with you guy's but I was thinking of putting 3 rubber grommets between the engine ang the firewall to help absorb some vibration. Is this a good idea?. Will the grommets hold up?. I intend to put this engine on a clipped wing cub 1/4 scale (Sig). I have the wing covered and tail feathers framed up with most of the fuselage, just the nose to do. I was afraid of vibration so I want to pin the front of the fuselage together with dowels and then glass the firewall. I think this engine should do the trick. What do think. I know it would be mighty handy to know how big this engine is, I hope the bench test may give some indication.

grommets
 

The grommets may not work. To much of a problem getting them to work good. Try solid mounting first. Have the engine tuned real good and broke in before you place it on plane. After you get it on plane watch the tail for vibes. You may need tail bracing. Extra insurance...so do it anyway. If idle is set to rich, it may shake more. Run this engine a lot first and get it fine tuned. Do your radio check with engine off and running also. Good Luck Capt,n :)

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Thanks Capt'n

Yes I will have tail braces as well. The engine had a couple of hours on it in it's former life as a weedwacker. I imagine it should be broken in. I intend to get 7000 rpm, if I get more than that like 8500rpm I will increase prop pitch and or size.

Gee I tought my rubber grommet idea was good. Thanks again

grommets
 

Good idea...just hard to get right....try it you may have good results. You can also buy lord mounts form a electric motor shop and they are cheap....I seen some thjat look like they should work. Got to go and shovel snow...not fun Captinjohn :)

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Well I promised to keep you guy's posted on tach readings. I don't think this engine can be a 28cc. With a 16x6 prop I get 7500rpms. Mind you that's with the supplied muffler and a carb with no mixture screws. It also has not been modified or hopped up in any way.

The good news is it idles well at 2000 rpms (I have not played with this yet) and I have seen two stokes vibrate more than this. It just purred with no vibs hardly at all.

So my next question............ would this be closer to a 25cc or 24cc.?.
Would these rpms be adequate to fly a 14lb clipeed wing cub?.Keep in mind I will be mod. the muffler and probably hopping it up. If you did not catch it the engine came in at 3lbs.

J3
 

It should fly it scale...my opinion... John

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Many weedwackers have a very small carb throat to restrict RPM so go to your local small engine shop and pick up a used one with adjustable jets. I dont know what size you have now so can't advise what size to get. Your small motor machanic should be able to advise you. It will make quite a jump in power output. Let us know how you make out.