I just saved an engine from going to the aluminum scrap pile. I want to convert it to RC use, but I have no idea what it is. From what I understand, it came off a leaf blower. I took the engine apart to check the bearings, and they are ball bearings. Both the flywheel and the carb have "Walbro" stamped in them. The flywheel also says "made in the USA". Directly under the exhaust outlet is "2A", and below that is "028776". I attached pics, but I don't know how helpful they'll be. Can anyone tell me what kind of engine this is, what size, and if it'll work on a plane? Feel free to ask anything about it that I didn't say, I'll do what I can to answer it. Thanks,
Grav

-edit to include the pics

kinda looks like an old zenoah g2d ...... but it does look a likely canidate ... if the compression good. what is the displacement?

no idea on the displacement. I'm guessing in the low 20 cc's

kind of looks like mine.it did come off a blower.its a 25cc poulan.2 rings as you know.large transfer ports.should be a screamer.backplate is already stuffed into engine.easy to convert basiclly.mine only weighs 3.5 lbs as seen in pic.after cutting and if i go cdi it should weigh a little over 2.5 lbs or a little less.i will do mine after im finished with my echo24 and my echo 61cc twin saw engine.if you need any help or have any questions get hold of me by pm first and then we can go email if you want or phone.bought mine from farley9n.maybe he will join in.

Thanks for the mention Buck! I believe you have called this engine correctly and also answered the question I had about; what ever happened to the one I sent you? I have been waiting for a comparison between it and the one you already had. I do have at least one more of those engines but have been reluctant to do anything with it until I knew more about how they would work out...........Bob

Hi,
I have an engine on the bench now that is exactly the same. I took it out of a Weedeater BV-200 leave blower. Mine is a 25cc, single pined ring with a 10mm Zama carb. It has a four bolt backplate, bolt on muffler and a long shaft (5/16x24) with a flat milled on the shaft. The hub used for the impeller is well suited to convert to prop use. It uses a washer at the flywheel, a steel tube spacer and a keyed impeller driver that can be cut down to make a great prop hub. You just cut off the portion that keys into the impleller. When done you will have a powerful long shaft 25cc airplane engine at about 3.5 pounds with mag. The carb is the correct size at 10mm, but the exhust is on the small side. Mine has a aluminum slevve in the exhust, when removed it leaves a 1/16th lip accross the top of the exhust,flish with the bore. It would be very easy to remove this material and chanfer the port edges to enlarge the port and advance exhust timing. I need to throw a degree wheel on it to find out where I am now and how much material needs to be removed. The idea is to match the stock Homelite timing to start. It will be a little weak with existing timing. The compression can be easily increased, because the cylinder doesn't have a flange and is flat on the bottom. This allow it to be milled or filed carefully down after taking measurements. It looks like a great engine for conversion.

Dave

Thats exactly what I needed to know. Everything you describe is the same on mine except, if I read your post right, you have a single ring on the piston. Mine has two rings - actually had two rings as I broke one when I took it apart to check the bearings. Everything else - the keyed shaft, steel tube spacer, and displacement is the same. Sounds like I have something to work with here. I am still wondering how to attach the prop. Once the shaft is cut down, what next? Are you planning on threading the end, or are you doing something else. I've seen conversion kits online that include a prop hub, but I've never done a conversion and don't really know how the hub attaches. I have two other questions that I think I know the answer, but I want to be sure. Since the recoil starter was already off the engine when I got it, I'm not sure which way it rotates. It looks like it should rotate couter-clockwise when you look at it from the front. Also, I'm assuming that the wire that attaches to the ignition needs to be grounded to shut the engine off and not be connected to ground for the engine to run. Thanks for your help,
Grav

Hello Gravityisnotmyfriend,
To answer your questions. Mine has a single pinned ring. You can use a feeler gauge blade of about .008 or so to ease rings out of the grove without breaking them. You don't have to thread the shaft. Use the parts that came with the blower or der some with the rings, if you don't have them. The hub that went into the blower impeller should make a nice prop driver. I am attaching a few pictures that I just took of mine to show how it should look. The hex section that is inserted into the impeller will be cut off with a hack saw and carefully filed flat. This will make an engine with a very long shaft and will fit nicely into a streramlined cowl, such as my Goldberg Ulimate. The engine turn counter clockwise when viewed from the flywheel end. The case and back plate must be trimmed to save weight and provide a flat surface for the mounting plate. I weightd the parts and it should weight about 57 oz. mounted less prop. The long shaft will also move the engine back for easier balancing.

Dave

Here's a couple of pics that are a little better. Dave, I was wondering if you've ever used an engine setup with that long of a shaft. I hope you don't take offense to me questioning you, I'm certainly no expert. It just seems to me that if anything is even slightly out of balance, the crankshaft wouldn't last very long because of the weight being that far from a bearing. Also I still need to figure something out to mount the prop. I don't have that hex nut, I just have the tube spacer. That's why I was wondering if I needed to cut the shaft down. I also have a question about mounting the engine. I have four bolts that attach the backplate to the engine. Would these be strong enough if I just bolted a plate to them and attached that to the plane? Thanks for the help.

Hi,
I posted some pictures of mine in the conversion formum a few days ago. I asked the same question about possible vibration. Here is the post.

http://www.rcuniverse.com/forum/m_3107092/tm.htm

All of the long shaft trimmer engines use a unthreaded slip on prop hubs. Rethreading a hardened shaft is not feasible. You can order the hub from wackerengines.com with a 5/16" bore and the desired lenght. Most hubs are 1.5" to 2" long. This will have larger diameter then the stock spacer and will give the required support. You will need a spacer between the prop nut and the prop washer. This could be made from a section of the spacer that you already have. I am in the process of reducing the lenght of mine also. The engine is a good one for performance. It has large ports and transfers. The plate mount can be counter sunk and bolted to the back plate with four flat machine screw and blue locktite. The muffler and mount can be had from wacker also if you send Pete the patterns for both. Make sure that you indicate the maximum width to clear the coil bracket for the muffler. Good luck.

Dave

I have two Homelite 30cc engines that had the long shaft. I cut them to the desired length and rethreaded them. The shaft is not as hard as you think, but you need to use a good quality die.

AV8TOR

Hi,
Thanks for the tip. I need to get a hi quality tap and die set. My dies suck.

Dave

Most of the weedie cranks are not hardened and can be threaded with a good die.

I have had great success using a plain jane die set from Home Depot. I have threaded several shafts from Homies to Ryobis. You really just have to make sure to use some oil for the cutting and also make sure the die is exactly square on the shaft.

This is super easy to do, and makes long shaft engines really easy to convert, without any special parts.

Tom