Weed eater engine conversion

Well, Since new guys are asking stupid question I guess I will jump on the bandwagon. I am new to this forum, but I have read most of this thread. I am at the very beginning of this project and am trying to locate a brush cutter over 50cc that can be purchased at a reasonable price and be shipped to Alaska, anyone have a suggestion I would appreciate it.

 

www.ebay.com

 

Boat Motor

My buddy and I have made duck boat mud motor out of a weedeater and the motor runs fine but when you put in the water the motor dies. It is a straight shaft mud motor that looks similar to this.
http://www.boatdesign.net/forums/at...807905-weed-eater-engine-conversion-boat2.jpg
Can anyone tell me why?

 

the prop is too big either in diameter or pitch and the motor is unable to drive the load

 

Problems

I have the smallest trolling motor prop on it right now. Does the weedeater have to have a clutch on it? What is the easiest way to make this thing work as cheap as possible? Do you have more pictures and design plans of yours? Thanks for all of you help

 

For sale

How much would any of you would like to sell one of these weedeater motors for ready to go?

 

What kind of prop are you using? The cast aluminum props sold by Young's Props are small enough that they don't kill a weed whacker motor with a clutch.

Erich

 

your trolling motor prop runs at about 12-1500 rpm driven by say 1/2 hp so if you drive it at 5000 rpm + its too big a load ....less pitch is the main thing ..make your own prop from a twisted bit of metal and see how you go

 

Check out a hobby shop.

 

That's my motor

That picture you put a link to is of my motor on my Hoefgen duckboat. It is a 52cc motor that I purchased from Duropower as a complete brushcutter and pushed my boat 6.2 mph. They no longer sell this as a complete brushcutter but I believe you can purchase the same motor that came with my kit (look for their 52 cc motor.

Prior to this motor I built one using a 31cc bolens motor that I purchased at Lowes for $69. I followed plans put forth by others and incorporated some of my own design as well. This motor, no matter what I did, was unable to push my boat for a long period of time without dying. It would go for up to30 seconds and then just bog out. Trying different props from Young's didn't work. Had I spent the time to find the hop up parts for the bolens motor I bet I could have gotten it to work. I figured the time and money to do this would be more than just purchasing the Duropower unit.

Couple of questions. You say you used a trolling motor prop. Are you sure the prop will spin the correct way for the motor you have? I know it sounds silly but many have put on an incorrec rotating prop.

How big is your motor? My opinion is that anything less than a 49cc motor is not big enough.

Let us know if you have any other questions.

Mark

 

yup trolling moter props spin the wrong way..been there before.

 

Motor

Motor has 32 CC. The prop seems to be going to the right direction. How much does it cost to build one with the brush motor and to run like yours if I wanted to build one like it?

Thanks for your help, this thing is frustrating. Has anyone had any luck with a 32 cc motor, if so what size prop did they use??

 

I have been looking through this very long thread over the past few days. I am new here and I am inspired by all of the progress and designs on this thread. It really is remarkable.

I am planning on building a long tail mud motor similar to rippedoffs design with a few changed of my own. My motor I am using is a 6 hp techumseh.

I need some advise on where to get a decent priced prop for this motor. I don't really want to spend 150 on a prop. I would really be interested in building one but I dont know all too much about it.

Does anyone have any advise for building a prop for a mud motor or finding a decent priced prop. Any help would be appreciated.

Once again I am truely inspired by all of the inginuity and expertise on this forum.

Thanks in advance and keep on thinking outside the box.

 

I forgot to say that I'm not trying to break any speed records. I just want to push by 10' mini pontoon that weighs about 400 lbs loaded somewhere between 8 and 10 mph across the lake.

Any help appreciated.

 

More info

There are some that have built a 31-32 cc motor and made it work. Ripped says he has built many of them and they work fine. I believe the prop he is using is a T-10 from Young's. You would have to go back and read that part of the thread and make sure I got this number correct.

Myself and John O'Neal have had some difficulty with the smaller motors. Not trying to put words in John's mouth but I believe he had the same issues I mention above. It worked, it just didn't work great and it worked no where near as good as the 52cc motor.

Cost to build this one was probably around $250 or so maybe close to $300 - I can't recall exactly. OInly required the fabrication of one part and it was pretty easy to do.

Mark