Looking for some advice - sort of related to Motoredbikes

Discussion in 'Off Topic' started by Mark W, May 1, 2008.

  1. Mark W

    Mark W New Member

    I joined up yesterday after spending some time cruising around the site. Looked for the best spot to pose this question and I chose here - hope it's OK. With all the experience of building these motoered bikes, I'm hoping I can find some answers here.

    I've been fiddling around with building a happy time powered mud motor (see Rickshaw Motors for example of commercial $900 mud motor http://www.rickshaw-motors.com/) for my small boat. I also attached a pic of the commercial unit (Rickshaw1.jpg)


    I figure that after you have all built the motored bikes, maybe you will want to try to build a happy time powered boat. I'll be here to answer any of your questions when you get to building boats - promise.

    One area that I have been unable to solve in a reasonable manner (ie not spending $150) is gear reduction. With the rpm's these motors turn, a prop turning at those rpm's just cavitates. This isn't a big deal as you just use 1/3 throttle and you are good to go. The problem with this is that your torque is way down and going through any tough areas with this motor does not work. What I need is a 3:1 gear reducer.

    I am aware of the Staton 3.11:1 reducer and it looks like a good candidate but at $129, a bit on the pricey side. I also see some of those $30 Chinese 3:1 gear reducers and see that they basically do the same thing as the Staton unit. What I can't figure out is how do I interface bewteen the happy time engine and the drive shaft on the mud motor (see Rickshaw2,jpg). As you can see, Rickshaw built (or at least I think he did) a gear reducer that at 3.75:1, is a bit much in my opinion. He also mated this to a Honda GX35 engine that while a great motor, I have been told by Honda that this may not be the best motor for real cold weather use that my mud motor will see. Something about the misting oiling system not working soon enough while cold. Back to the gear reducer.

    The motor is attached to the prop via a 60" long 3/8" stainless steel driveshaft. The motor end of the shaft has been squared off to fit the motor chuck. The SS shaft rides inside a 1" OD, 3/4" ID aluminum tube on 3 oil impregnated brass bushings with grease zerts tapped right into the bushing itself. The driveshaft is attached to the happy time motor (bolens 31cc weed eater) via a set screw and the clamp that came with the week eater set-up. Not the best but it does work. Multiple seals keep the water out of the drive tube. I have 3 questions:

    1. Any suggestions on the best 3:1 gear reducer?
    2. Will it work with a 31 cc bolens engine (I don't know the actual engine manufacturer)?
    3. How will I attach the driveshaft of the motor to the gear reducer?

    I appreciate any and all help and assistance. My motor presently works but I know it could work better with a gear reducer. I'm already into the second generation motor and would like to do this one right.

    Thanks for allowing me to intrude upon the motored bike site. I can provide pictures of my mud motor if this helps any. I just can't figure out how to embed them yet.

    Mark W

    Attached Files:

  2. srdavo

    srdavo Active Member

    Hi Mark,
    I moved your thread here, to the white zone. Much more suitable for boat motors. :D
    (we can even talk, duck hunting, boats, blinds...you name it....this thread is yours!!)

    now......we can talk about your project. I like it!

    Last fall, a young fellow stopped by my garage, looking for some way to rig a throttle control on his home-built boat motor. (very similar to your set up. I'd never seen anything like it.) I found an old thumb shifter and a new shifting cable....$5 later, he was gone....grinning. he was powered by a 3.5 hp briggs, but sadly, I didn't check out his drive system. sorry:confused:

    we have a bunch of engine guys & fabricators here....someone will chime in & try to help ya....

    check this great thread about uploading pics. http://www.motoredbikes.com/showthread.php?t=9817
  3. Mark W

    Mark W New Member

    Poor quality pics of my happy time mud motor

    Not the best pics but I wanted to see if I could upload the actual picture into the thread itself.


    OK, it isn't working. Does it have anything to do wtih my posting rules saying that my code is off[/B]

    Mark W
  4. srdavo

    srdavo Active Member

    your pics look fine.
    did you build this? It's cool!!
    Is this the engine, (in the pics) you want to do the gear reduction?
  5. Mark W

    Mark W New Member

    Thank's for the comments. Yes, I did build it. The motor I got from Lowes by purchasing the Bolens 31cc curved shaft trimmer for $69. I placed aside everything below the motor and built my own driveshaft and everything else on the thing. The prop I found online. It is nothing like building what you guys have put together on this site believe me.

    This is one motor that I would consider putting a transmission on but I do not think this is the final mud motor I will be going with as I will need more power than this motor puts out. This was a cheap way to build prototype #1 so to speak. I also think this motor will be hard to retro fit other stuff on to.

    There is a company in California called Duropower http://www.duropower.com/item.asp?PID=45&FID=13&level=1) that makes a nice 52cc motor that puts out about 2 hp and it comes with a nice stainless steel shaft and just about everything else you would need to make a nice little mud motor for $179. I have also been told that this is a poplular engine to get hop up parts for that would make this motor put out about 3 hp. This tied to a 3:1 gear reducer would make the perfect lightweight mud motor for my small marsh boat.

    Or, if anyone has a better suggestion for a small, lightweight motor where I can easily tie one of these Chinese 3:1 gear reducers and a pull start to, I'd go this route and build another drive tube as this is easy to do.

    Looking for suggestions.

    Mark W
  6. Mark W

    Mark W New Member

    Finally completed

    If anyone is interested, I finally finished my mini mud motor. It took some time and some figuring and all but I am happy with the results. I clocked 6.2 mph on the gps which is about as fast as I want to go with this boat and motor combo. The pic below is not the final configuration but you can at least see it working. Since this pic was taken, I've changed the tiller, the mounting to the boat, and a couple of other items making it more user friendly. The Duropower motor made all the difference verses the older Bolens 31 cc. motor experimented with the first time.

    Maybe I now need to build a motorized bike and trailer to haul the thing to the landing.

    Attached Files: