Yankee John

I pulled a Craftsman 25cc leave blower out of the dumpster in my complex the other day. It was still full of gas! I'll take "Free" any day!

Brought it home and I couldn't get it to run- figured that is why it was thrown away. I took off the plastic casing and discovered why it didn't run- the cylinder was loose on the crankcase! At this point I decided to use it for something other than a leaf blower. I understand that this is made by Poulan for Sears. The casting date is Aug 2001 so it's a few years old.

I don't have a plane for this (yet), But from several hours of reading posts in this forum, I understand that I have to cut the crankshaft down, fabricate a mount, possibly change the carb, and decide if I want stock ignition or glow plug/gas conversion (probably glow).

Here's what I need to know:

- How short to cut the crank, and what thread size/pitch (diameter is 5/16" ).
- What prop adaptor to use?
- Where to find the glow plug adaptor?
- What exhast will work on this engine?
- Last, The carb is a Zama C1Q-W11A with choke, primer bulb, and metering screws; Can I use it or should I get a Walbro (and use what adaptor?)?.

Here are some before pics; I have already cut off most of the aluminum shrouding on front, and trimmed/smoothed the rear crankcase cover. I still need to smooth & blend it all in.

Thanks in advance for any questions that you can answer!
John

Ralphbf

My Feedback: (27)

With a shaft that long a guy could make a mid engine 90 size aircraft.

I have one 0f these too, please keep us posted..

Yankee John

I put my engine on a little diet Lots of grinding & blending yet to do, but it is starting to look good.

John

Ralphbf

My Feedback: (27)

What does it weigh now?

Yankee John

That I don't know ralph, as I don't have a scale. After I finish blending and polishing the case, I'll take it somewhere to get weighed.

I was also surprised to find out that the crankcase isn't aluminum. It's a magnesium alloy. Lighter than aluminum- just don't start it on fire!

John

Ralphbf

My Feedback: (27)

The Post Office is a good place to weigh stuff.

btcmed

John, I just did the same thing myself with a weed wacker enging. I am using a fish scale which you can pick up at any sporting goods store. Even Walmart. It weighs up to 12 pounds but you can get bigger ones. After I cut and grinded my engine down, it know is 4.5 pounds with stock muffler and carb, and home mede mount. I have a short 5/16" x 24 shaft. Any help on a prop. mount for this engine?

carlosponti

My Feedback: (1)

I just bought a digital Berkley fish scale for 20 bucks that weighs stuff up to 50 pounds and can be switched to metric if that is your thing.

ps make sure to clean the engine out real good not to leave any of that metal dust inside the intake port.

tinsink

I have a 25cc that I bought in a power head off ebay. It looks to be the same casting and cylinder and it has a Zama carb with a big plastic adapter. It is explained in the $25 poulan conversion as to how to mount it. your drive shaft has to be cut way down. The one that I got off of ebay has one that did not need mods and it is the std 5/16 X 24. If you are going gas/ glow I recommend that you do not throw away the fly wheel.
you can turn it down to about 1.5 in. diameter and use it as a back plate for the prop. Plus its' keyed so it can help the prop from spinning on the hub. I used a piece of 5/8 hex 6061 aluminum and turned it to (I think) .4375 in. diameter leaving about 1/2 in of hex on the end of the adapter to use to tighten it onto the 5/16 X 24 shaft. And to do that I had to drill a hole through the center of the adapter and tap it for the 5/16 X 24 thread. By the way, I cut the adapter length for a Master Airscrew 16 X 8 classic prop. So that the prop hub i.d. is .4375 and it fits onto the adapter and then is sandwiched between the cut down fly wheel and the hex shoulder, of course I used a washer on the hex side. The adapter o.d has a length that is about 1/8 in. shorter than the thickness of the prop hub and washer so that the hub will sandwich against the cut down fly wheel.

Yankee John

Thanks for the info tinsink- This is exactly the type of information that I am seeking!


John

Yankee John

Here is an update on the conversion of my 25cc Poulan leaf blower motor.

I made a motor plate/mount out of a piece of 1/16" thick carbon fiber that I had laying around. Very light and very strong. Rough measurements are 3 inches by 3 15/16 inches.

I also shortened the carb mount, hoping to tuck it in a little closer to the engine. I cut approx. 7.75mm from it's length, then used a flat surface and sandpaper to finish it.

I'm still not sure on what I will do for a prop mount; I may buy a commercial adapter, or I might do something on my own. I'm leaning toward a Wackerengines adapter at this time.

Let me know what you think!
John

tinsink

YankeeJohn,
Did you just take 7.75mm off of the carb side of the spacer? Did you have to modify anything else?

Yankee John

tinsink, Yes- I took the 7.75mm off the carb side.

I also cut off a bunch of extra material from around the perimeter of the carb mount/spacer (that held the original air filter in place).

After the "surgery" the mount/spacer is now 21.8mm thick. There are still sufficient threads in the mount to bolt the carb on, as well.

John

Frank B.

My Feedback: (1)

Hi John, looks good.

The parts from wackerengines for the poulan are good, I use there prop adpter and the exhuast muffler on mine.

Currently flying the seagull yak 54 with the poulan conversion,

here is a link to my thread on how I did mine http://www.rcuniverse.com/forum/m_5849783/tm.htm

Yankee John

Thanks Frank. By the way, I think that your Yak is drop-dead gorgeous! It has caught my attention in a banner ad on this websight (???).

Just a mini update on my progress so far. I opened up the exhaust port to the size of the exhaust exit size. Mine was quite restricted, as is common on the leafblower versions on these, I hear.

I have also decided to paint the cylinder and crankcase with high heat ceramic-type engine paint. I was going to beadblast these parts, but I have seen several beautifully painted conversion engines here that helped me make up my mind!

Thanks again!
John

Yankee John

It's been a few days and I have had a little time to work on my conversion. I threaded the crankshaft to 5/16"x24, then shortened it to standard length.

I also painted the engine with Dupli-color brake caliper paint (degreased, painted (3) light coats, then baked in the oven at 250 degrees for 1 hour). I'll let it sit for a few days before I assemble the motor.

Lastly, The glow plug adaptor arrived from Horizon Hobby. Nice unit!

Now, Just have to order the prop adaptor, muffler, and carb velocity stack from Wackerengines and I'll be set!

I might be jumping the gun here, but what prop would be recommended with this engine on a BUSA Eindecker 90?

Let me know what you think,
John

ellas1

My Feedback: (2)

john, that looks real nice. i do many conversions my self. i have many poulan, homy engines. if you want an esier parts source, try outdoor distributors.
by the way nice paint job, i powdercoat all my engines. i find it to be more durable. and cool colors too.

cheers mate.
john.

spiffymafied

What did you use for a degreaser to clean up the engine before painting? I'm going to do the same thing with my conversion.

Yankee John

I used a can of brake cleaner that I got at a local auto parts store for $3. Works great and dries with no residue.

John

JIMARRINGTON

John,

Have you got your engine running yet? I just picked up a couple of these 25cc featherlite string trimmers from a local repair shop. Asked if he had any junkers laying around and when I left I had 2 25cc featherlites and 3 31cc Ryobis in the bed of my truck. Don't know if any run but hopefully I can scrounge one or two out of the parts. The price was right anyway. 0 dollars.

Jim

Yankee John

Hey Jim. I don't have it running yet, as I still have to order the prop hub and muffler from wackerengines. I did do the final assembly of the motor though. It is gasketed & sealed and ready to go.

John