To those who want to convert a weed eater...

Weedeater conversion Russian translation

I translated a Russian web page with a weedeater conversion here:
http://www.flapdoodledinghy.com/GD.html

The original site is here:
http://iv70.narod.ru/IV/9/GD.html

Bill

 

This is a dumb non-working idea.

Just read the previous messages. Ignore all the people who say they THINK it will work, read the people who have said they TRIED IT. A string trimmer motor doesn't have the power to push a boat.

Yes, you can put the prop into a lathe and whittle it down until it's tiny enough so the motor doesn't die, but then you have a little toy that won't push squat. Yes, you can modify something with a much larger motor, but then it's not a cheap, light, simple thing anymore, is it? If you are willing to re-engineer a $500 brush saw, why not just go down to Sportsman's Warehouse and buy a $500 outboard which works correctly out of the box?

Think about it. If a 50cc trimmer motor would push a boat, why wouldn't Minkota make one and sell it? The reason is, because they would all be returned as non-working. Simple as that. Take a piece of string and twirl it in the air. Doesn't take much power, does it? Now paddle a canoe. Takes a LOT MORE POWER, doesn't it?

(I have worked on several related projects, both trimmer motor powered and outboard projects. There is NO WAY a small gas trimmer has enough power to push anything that will carry a man. You'll just have a noisy embarrasment that dumps oil in the water. Pour the oil in the water by hand and save yourself the noise and hassle.)

Still not convinced? Think the big outboard makers are hiding some genious secret from you? Then view the video posted by some pinhead who "patented" this "invention". It's earlier in this thread. See for yourself. It only works going downstream! That's right, it only moves forward if the water is already moving in that direction. When when he tries to move against a light current he zooms in the video so you can't see the boat isn't moving. (Ask yourself, why didn't he test it in calm, non-moving water? HMMM? Because it doesn't work, that's why.) If you're dumb enough to need a motor to go downstream, then this is the perfect project for you.

Sheesh.

 

tomdeering is an idiot

The only part of tomdeering's post that you need to pay any attention to is this:

"Ignore all the people who say they THINK it will work, read the people who have said they TRIED IT."

You just gotta love an internet expert

tomdeering has obviously not tried it or simply gave up. I on the other hand HAVE tried it. I have built several of them and they work great. I started messing with them in the late 90's. ddomp's patented design is a carbon copy of the first prototype that I shared pics of on various web forums two years prior to his patent date, which is why I chose the name ripped off. That design with that prop is junk, believe me. But with the right prop in the right configuration it really comes alive.

I developed mine to power my layout boat. Despite what he says, you don't have to spend a fortune on a 50cc to make it work. I use a regular 30cc trimmer motor and can build the whole thing for about $150. Thats a scratch built drive, not just a conversion. They are also not loud as many people seem to think. You have to realize these are running about 1/3 throttle and under load, so you can actually talk to your buddy while motoring to the hunting spot. It's not like whirling a spool of line at 30000 RPM at some weeds. They will push a layout boat at about 6 MPH fully loaded. Mine has been in use for several years now, and I have pushed loads of up to 15 dozen decoys, myself and all my gear. I have towed another layout boat against a 20 MPH head wind, and can even break 1.5" ice. They will also get about 3 miles out of that tiny tank of gas.

You can see pics of my design and even instructions on how to build it on the weed wacker thread in the DIY Marinizing forum.

 

Hey Tommy, you idiot....

Thought it didn't work.

Look, calm, non-moving water! And no $500 50cc brush saw either.

Theres probably about $60 in the converted unit and maybe $150 in the scratch built unit, including the cost of the powerheads.

Not the fastest motors out there, but just as fast as any other 1HP engine, and just right for the type of boats I use them on.

Pushing a load of 15 dozen decoys in a 14' wooden boat


A couple of my motors. A cheap and easy "conversion" in the foreground and a scratch built drive in the back.


A buddy in an Otter Stealth.



Video clip.

 

After the responses that it was not possible, I just had to do it.
http://www.flapdoodledinghy.com/motor.html

I could not be happier with my little 9 pound outboard.

Bill

 

This website is not working www.weedwhackerboat.com

Also, would'nt you be able to use a blower attachment as a propulsion system? just put it on and stick it in the water.

 

I have bought running garage sale weedeaters for as little as $20, I have bought running ones but with damaged heads for only $5 (I bought it for parts).

Looks like a fun little toy, maybe I can use it in my kayak, it only has about 4 pounds of drag at 4 knots if I recall.

 

You have to use a smaller and smaller pitch prop. Also, don't start the thing out the water and push the prop in the water. Start it in the water so it's under load. You may also have to adjust the timing on the weed eater motor - it is set to run almost without load, you want to run it at full load.

 

Percy Blandfords book canoes and canoeing with sideboard "weedwhacker" motor

Thanks for all the great info, I am reading Percy Blandfords old book (1962)canoes and canoeing and he has a photo in the end of the book of a little kayak using a 1/3 HP motor. He says they are called sideboard motors and will push a canoe faster than can be paddled all day while doing 18 hours to a gallon of petrol. I am assuming he means English Imperial gallons, but still!! I am amazed at how much the little sideboard motors look like weedwhackers. I don't need to go fast, just want to see how far I can go on a gallon. I will be making my own weedwhacker motor and will let you guys know how it goes.

Robb Moffett

http://robbmoffett.googlepages.com/

 

The only thing I can tell you is yes they will work. The following link is a short video of mine. I'm going to try a new gear reduction and prop combination soon... hope it works better; good luck
http://www.youtube.com/watch?v=xM6bBX4XZcc

 

Guys,

Do not overlook your local hobby store as a resource for props. Weedwacker engines are frequently used to power larger R/C speedboats. The propeller companies like Octura make props that are perfectly suited to your need with two, three and four blades, designed to dissipate 1 1/2 to 4 Hp and mid thousands RPM range. You will even get a selection of materials; plastic, beryllium copper alloy, or SS. Some of you may not have a hobby shop close by. Then there's always ebay. Look at item 260271240650. Yes the metal ones are pricey; that's the rationale behind plastic. What you do is take your first guess for the right prop and buy the pitch and diameter in plastic. you try the prop out on the water and if you think it's just right, buy it in metal. If not, try another cheap plastic prop until you find the 'goldilocks' prop for your boat/motor. A typical price for a good metal prop in your size range (about 3" diameter) is about $40. Plastic runs about $12. The manufacturers make a bewildering variety of these props, so it would be wise to seek advice from a knowledgeable seller.

Jimbo

 

I cant find anything on that website about the weed whacker boatmotor. talk about hard to navigate. I am 13 and just finished my first outboard:~)! yay!!!
i made a prop that works like a jet ski does. it provides an enormous amount of thrust and it is all made out of scrap. it doesnt get to hot and only needs to run at half throttle to provide the same amount of thrust as a normal prop does at full throttle. it will always win against a conventional style prop and if anyone is interested i can post pictures of it.

 

Free Plans Online Successful Weedtrimmer Conversion


This guy figured out how to do it take a look. Free downloads... Check out the patent section.
http://underwaterprojects.741.com/outboard.html

 

I like my idea better: Using a Weedeater motor and a small alternator to re-charge the battery, that drives the Trolling motor, that drives the boat!

That way you only have to put up with that Obnoxious Weedeater while the Batter is being re-charged.

 

Looks fake