weedeater mud motor

Thread starter #21


Senior Member
New pics

This is the latest prop it worked ok but still the rpm is not where i want it to be. It seems to me the smaller the diameter the more rpms i get out of the motor so i'll cut down this prop alitttle at a time. I've been sick with a virus so it might be a few more a days before i get a chance to tinker with it.



Senior Member
Good Luck with it!! i know it is hard taking all of the jokes but I hope it works so you can prove everyone wrong!


Senior Member
i have to say this is one of the best thread i have ever seen on this forum....that being said, im laughing my *** off right now too! great idea, and i hope it works...im sure there were a lot of folks laughing at the wright brothers before they got the plane off the ground....remember all the ribbing Noah took for the ark....we may all look back and wish we hadnt laughed at you!
I couldn't resist, but I have been know to eat my own words! I can take it.:clap:


Senior Member
I wonder if you could mount that thing farther forward and put a rudder on the back? I've got a 12' john boat that needs a motor, maybe I could use your idea to work something up for mine. Yes, I am a redneck!:bounce:
Thread starter #28


Senior Member
Well I have not done anything w/the motor this weekend but will have some time next week to tinker with it. The rudder/skeg idea is a definite must but right now I'm trying to figure out how to get more thrust out of the setup. The best idea I have now is to get a gear head off one of those brush cutter or edger weedeaters I think they are also like 2:1 gear ratio. That should get more torque to the prop and let the motor run near full rpm. If anyone knows about these type gear heads let me know.
I thank yall for all the feedback both positive and in fun. I get a kick out of checking the forum to see all the replies. I am a pretty secure guy that has found good success in my profession and i don't post on here or anywhere else for approval from others. Keep the ideas and comments coming.

One other thing that i would like to make clear is that, the weedeater mud motor was not my idea. I saw this on another forum and decided to take the project on. What i cannot figure out is why some people don't see the relationship between this project and a go devil. I know this will not be a very powerful motor but for a canoe or gheenoe it just might push it pretty good.
What i cannot figure out is why some people don't see the relationship between this project and a go devil.
I hate to break it to you, but there is no relationship between a 25cc Weedeater motor and a 6.5hp Briggs & Stratton (which is the smallest Go-Devil offers). I'm not trying to be mean, as I applaud you for your ingenuity. But I don't think you will ever make the motor work for your purposes (at least not as well as you think).

I know this will not be a very powerful motor but for a canoe or gheenoe it just might push it pretty good.
The only way this would ever get the boat going "pretty good" is over the other side of a big waterfall.

Just kidding, I'll buy one once you patent it!!
Thread starter #31


Senior Member
There is a guy that got this going. I think it is rickshaw motors, do a google search. He put a gear box on it, it seems to do ok and would be great for a very small boat like a canoe or some type of layout boat.


Senior Member
Don't be so quick to knock the idea. I saw a guy build something similiar for a gheenoe using two trolling motor engines. I saw it on Lake Iamonia in Tallahassee, Fl, where you can't have an internal combustion engine.
i have often wondered if you could use a 3/4 wheeler engine or even a motorcycle engine with the transmition so you could shift it when ever you wanted....

i dont see why it would not work.... its 4 stroke.... its quiet.... you can gear it down for slow manouvering.... you can gear it up for haul a.....



Senior Member
i have really been thinking about this same thing but just using a go cart motor or lawn mower. I do like how the mud devils come straight off the shaft but what if you hit a stump? Does it break your pin or strip gears or does it just kick up. I like the scavenger back water motors. The are belt driven and it seems if you hit somethin with them it will just slide the belt. But great idea. I hope it works out well for u. prove em wrong!!

link to backwater

I have yuor answer. First you need to scrap the weedeater motor. Even if you figure a prop configuration that get the RPMS you need, you will never be able to sustain them because of the lack of torque those motors put out. Your answer in economical power is a 5hp verticle shaft Sears Roebuck lawnmower engine. These are all over the place and can be purchased for about $75. This engine is ideal for two reasons. First, it's a verticle shaft so the engine can be mounted on a platform that will swivel and tilt while allowing the shaft to stick straight off the back of the transome. Secondly, these motors are made with anti-cyphoning mechanisms that keeps oil and fuel flowing in the right direction, keeping fuel feed consistent and cooling the engine properly.

With the 5hp rating, these mower engines create enough torque from the start to propel a boat at a good clip. You can simply make a long tail by taking a piece of keyed shaft and coupeling it to the motor via a 4 bolt plate. Easy to machine one from some flat stock and drilling and tapping for thru-bolt connection.

As for affixing the prop, again a machine shop can spline and thread the end of the shaft for a reasonable amount of money. to protect the shaft and the prop, you can encase the shaft in a larger diameter pipe and keep the shaft centered with pillow bearings. Then weld a plate skeg with shroud around the prop and you have added protection and spine to your tail. All together, you might have $400 into it and should push your boat at about 10-15 mph, loaded. You can even use an external gas tank with a ball valve to afford you greater range as the engine has an internal fuel pump.

I will be attempting to make one this summer, once turkey season is over. I'll keep you posted on how it goes. But I have a feeling it should work well as I have seen one already and my lawnmower mechanic tells me this is the best engine for the job. Good luck.


Senior Member
you will need a horizontal shaft not vertical.