Lawnboy Engines?
06-13-2003, 01:57 PM
#1
Lawnboy Engines?
Has anybody done anything with a Lawnboy engine yet? Seen some new 4hp engines on **** for $110 to $130. There new one is 6.5hp. At that rating according to ThrustHP, would give 5500rpm with a 26X12 Zinger, 62.5mph top speed, and 39lbs of thrust. Sound possible? They don't list any displacements though. They do seem like very smooth engines from the ones I've seen. Oh btw, one has oil injection!
06-18-2003, 03:53 AM
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Lawnboy Engines?
I HAVE SEVERAL BIG CC'S CHAINSAW ENGINE, SPECIALLY MCCULLOGH, 54.5CC AND UP, 7 OF THEM, THE 2 LAWN BOYS, I WAS TRYING TO MAKE INTO A TWIN
06-18-2003, 09:02 AM
#5
Lawnboy Engines?
I have a Lawn Boy weed whacker converted to a airplane engine. It's identical to the Ryobi. I also have a Ryobi. There's no difference except the color of the plastic that was on them originally.
I would expect the Lawn Mower engine to have simular materials as the weed whacker for the engine is made by IDC also. I know they look a little different. You will also have to saw off the mounting flange from the mower version.
Judging from what one mower engine will cost new, it would be cheaper to convert a chainsaw.
Jim
I would expect the Lawn Mower engine to have simular materials as the weed whacker for the engine is made by IDC also. I know they look a little different. You will also have to saw off the mounting flange from the mower version.
Judging from what one mower engine will cost new, it would be cheaper to convert a chainsaw.
Jim
06-18-2003, 12:17 PM
#6
Lawnboy Engines?
"You are bidding on a brand new "M" Series Commercial Grand LawnBoy 4 HP engine. This engine includes gas tank, start rewind assembly and oil injection system."
Direct from ebay. Cost: $110. Not too bad. Of course I cant find any displacement for the Lawnboy engines though.
Direct from ebay. Cost: $110. Not too bad. Of course I cant find any displacement for the Lawnboy engines though.
06-18-2003, 01:35 PM
#7
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Lawnboy Engines?
Most lawn mower engine these days are 4stroke engine. As such, they are likely to be too heavy for even a big wing Cub.
There are a few 2stroke lawnmowers around. Not sure if Lawnboy has any. In fact, I just saw a new neighbor, apparently a first time home owner, smoked a brand new mower a week ago. The thing first started to belch blue smoke not longer after he started cutting grass, then it turned into thick clouds of white smoke. By the time I turned my truck around to stop him, it was too late.
As for the HP rating, that's usually peak motor BHP at a certain RPM, which means little in RC usage. Even if you have the HP and torque curves for that engine, I doubt you could correlate it directly to the HP figures in ThrustHP.
There are a few 2stroke lawnmowers around. Not sure if Lawnboy has any. In fact, I just saw a new neighbor, apparently a first time home owner, smoked a brand new mower a week ago. The thing first started to belch blue smoke not longer after he started cutting grass, then it turned into thick clouds of white smoke. By the time I turned my truck around to stop him, it was too late.
As for the HP rating, that's usually peak motor BHP at a certain RPM, which means little in RC usage. Even if you have the HP and torque curves for that engine, I doubt you could correlate it directly to the HP figures in ThrustHP.
06-18-2003, 04:34 PM
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Lawnboy Engines?
THE 2 LAWNBOYS I HAVE ARE SINGLE CYLINDER 2 STROKE, AND SHOULD BE ABOUT 100CC OR SOMETHING LIKE THAT. THE WEIGHT IS AROUND 7 POUNDS, THE ONLY THING THAT WORRIES ME IS THE VIBRATIONS, THATS WHY I WAS GONNA MAKE IT A TWIN... CURRENTLY MAKE A TWIN WITH 2 HOMELITE 25CC, FINAL WEIGHT SHOULD BE ABOUT 3.5 LBS
06-18-2003, 05:26 PM
#9
Lawnboy Engines?
Lawnboy engines with the exception of one mower (Tecumseh 6.5hp 4 stroke) are 2 stroke 140cc engines. The older engines are 121cc. The new ones are double ball bearing supported cranks, the older ones are needle bearing supported cranks. I think the new engines might have some potential. Even if the power is lower in the rpm range, use more pitch.
Lawnboy mower: $299
Ignition: $130
Muffler: $100
Conv. parts: $100
Rough total: $629
140cc Rc engine: $1500
Mufflers: $150
Total: $1650
Savings: $1021
For that kind of savings, why not try it. Am I a TOC Pilot? NO WAY!
Do I need a TOC type engine? Nope. So why not try something to save a little so I can fly bigger planes? I already have a GSP.com Edge 540 (103" version). That's why Ive been working on the Tecumseh engines. The Lawnboy seemed like another alternative.
Lawnboy mower: $299
Ignition: $130
Muffler: $100
Conv. parts: $100
Rough total: $629
140cc Rc engine: $1500
Mufflers: $150
Total: $1650
Savings: $1021
For that kind of savings, why not try it. Am I a TOC Pilot? NO WAY!
Do I need a TOC type engine? Nope. So why not try something to save a little so I can fly bigger planes? I already have a GSP.com Edge 540 (103" version). That's why Ive been working on the Tecumseh engines. The Lawnboy seemed like another alternative.
06-20-2003, 02:43 PM
#10
Lawnboy Engines?
Lawnboy's are 2 stroke, don't think they ever had a 4 stroke. But for a 2 stroke they still look big for the power output. The 4 stroke engines have a rugged crank and case to take lots of blade strikes, because of this they are large for the displacement. I suspect the Lawnboy 2 stroke's would be the same. A small motorcycle engine would make a better conversion, if you could cut away the transaxle part.
06-20-2003, 03:38 PM
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Lawnboy Engines?
I'd say the LawnBoy is a perfect candidate for a conversion. I've run them for years and they're pretty tough, they'll take a good prop strike without damage. I'd say a hidden stump or a kid tossed rock in the lawn is the same as any prop strike it may encounter at the flying field. And another reason the LawnBoy would make a conversion: you already know it will swing prop well, under load. After all that's what it's made to do.
06-20-2003, 05:30 PM
#12
Lawnboy Engines?
The only draw back(s) I can see are lower rpm range and vibration from being a single cylinder engine. I have never owned a Lawnboy, but have used them. As a mower they seem smooth, but without the flywheel it may tend to vibrate more. I got my Tecumseh 138 down to 8.25lbs, I tend to think the Lawnboy (141cc) may do better.
06-21-2003, 12:41 PM
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Lawnboy Engines?
My neighbor tried real hard to give me a Lawn boy, had to say no. Have an image of a Briggs 2 stroke engine 141cc before and after if someone can post it.
06-21-2003, 06:38 PM
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Lawnboy Engines?
Have a twin cylinder based on two of these engines. Also have a real backpack engine, a 320cc JPX twin cylinder. Oddly enough if i download the posted image ov my engine, it still shows up as 180k, too big to post from here???
06-21-2003, 06:50 PM
#19
Lawnboy Engines?
both pics are about 62k and shouldn't change any if you download them, must be a problem somewhere.
wow! a 282cc twin sounds great but i don't even have the time to do any type of sailing these days so i guess it'll have to wait as a winter (no such thing here) project.
dave
wow! a 282cc twin sounds great but i don't even have the time to do any type of sailing these days so i guess it'll have to wait as a winter (no such thing here) project.
dave
06-29-2003, 03:03 PM
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Lawnboy Engines?
I have two lawn boy mowers that are 2 cycle. I looked at these for conversion, but noticed that the carbs have floats. Are you anticipating changing carbs on the engines or do the newer lawn boy lawn mower engines have carbs without floats? I figured you'd have to cut away alot of the engine mounting flanges to make them light enough, but they are pretty large engines.
Paul
Paul
07-01-2003, 05:19 PM
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Lawnboy Engines?
I have read all the posts in this thread but haven't seen anything written about anybody putting one of these converted engines in an airplane. Do you guys actually fly these engines or is it all an exercise in futility. What gives? I'd like to know what airplanes you've got them in if any of you do and what kind of performance you've gotten. Cheap is good only if it works!
07-01-2003, 06:07 PM
#23
Lawnboy Engines?
I suggest making a copy of a Lawnboy mower out of balsa, plastic, styofoam, and foamboard. The deck would be a screen or expanded metal, then some heli blades instead of mowing blades. I think this would be the best way to make this engine fly!
02-29-2004, 06:05 PM
#24
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RE: Lawnboy Engines?
Thought I'd add my nickels worth. Pictures, if they uploaded, are of an F-series short block by lawn-boy. I just received it in the mail as a long term project. It's quite different from the M-series that I saw pictures of here earlier. I'm interested in keeping the weight down so I think I'll be converting this to E85 glow fuel to see how it runs. I've been following another thread that has really introduced some interesting concepts that are worth trying. This particular engine has the carb mounted below the crankshaft. It is listed with a carb having a .5" venturi but I'd think it should support something larger. I've got a WJ-10A that looks like it can be attached using an adapter. The carb flang is square and has a reed on the inside and there is a pressure tap located in the flange. There are cast-in lugs that could be used for mounting. I believe the long shaft PTO side needs to be cut off and a tapered hub cut for the prop. I haven't confirmed the displacement yet but it looks to be up around 120 to 140 cc's. It is pretty short stroked and appears to be on ball bearings from a diagram I downloaded from lawn-boy. There is a bolted on assembly that is part of the blade brake; it comes right off. I haven't weighted it yet but my guess is that it weights as much as two of my ST 4500 engines. I've got a really large bi-plane in mind as its future home. I don't think I'll need to add any additional weight in the nose for my overweight tail. Anyone have any thoughts as to a starting point on the prop?