Weed eater engine conversion

Discussion in 'DIY Marinizing' started by Ward, Jun 2, 2003.

  1. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    Helicopter John Where Are You?

    Helicopter John posted an excellent longtail project, based on the Honda GX-35 4 stroke weed trimmer engine, back on page 80 -90. He mentioned other projects he was working on. Would love to see more posts from his capable shop skills.

    Maybe the Honda GX35 worked so well there was no reason to build other versions! We'd love to hear about what you've been up to, John. Hope you're doing well and building more of these little engines.

    Any ideas about something for kayaks?
     
  2. YotaTruck
    Joined: Jun 2013
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    Location: NJ

    YotaTruck Junior Member

    Looks like Erich hasn't posted in about a year, but from I've seen, his conversion is the best out there, and the videos are the most informative as well. I'm considering building a very similar motor out of an Echo commercial grade 30cc trimmer (same type of gearhead) and an old Gamefisher 6 x 6.25 three blade prop. It might be too much for it, but I won't know until I test it I guess. I'm looking for a cheap and easy way to power a trimaran canoe-16' canoe with 8' outriggers/stabilizers. Total weight of about 900lbs-not looking for speed, just to be able to travel across the lake and back without paddling.
     
  3. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    Hi Yota Truck, I hope that works for you. Please post pics and keep us updated on your progress. I have a good lower unit myself, it's from a 1.75 HP Gamefisher, that has a bad crank from a loose flywheel key. I bought it for scrap value out of a metal scrap yard. I'd be interested in seeing how you mount the power head to the lower unit. Good luck, and I hope it does what you're wanting it to do.
     
  4. YotaTruck
    Joined: Jun 2013
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    Location: NJ

    YotaTruck Junior Member

    Actually its the other way around. I'm thinking of mounting the Gamefisher prop on the weedeater for use as a longtail type motor. I've also considered mounting a 5.5 HP HF Predator prop on the Gamefisher leg (it's a 7.5HP)-the motor is actually good, but they are not known for reliability and parts support is almost nonexistent.
     
  5. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    You're right about the lack of reliability of these older Gamefisher motors. I have two others, a 1.2 HP and a 3.5 HP. I can use the 1.2 HP on a side mounted transom on my Stealth duck boat, but it's so noisy I hate to use it when fishing.

    Helicopter John's setup, using the Honda 4 stroke engine, is one of the best long tail setups on here. I've bought the engine and materials, but haven't put it together yet. There's pretty good coverage of it starting at about page 80 -90 in this forum. He has lots of pics and some videos posted. You might want to check his posts.
     
  6. Erich_870
    Joined: Feb 2009
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    Location: Juneau, Alaska

    Erich_870 Junior Member

    I'm still kicking around, just been super busy for the past year. I have a handful of different weed whackers I want to turn into new motors. Just need the time...

    A three blade prop that big will probably bog down the engine to the point it stalls, but like you said, give it a try! Nothing ventured, nothing gained!

    Be sure to post pics!

    Erich
     
  7. YotaTruck
    Joined: Jun 2013
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    Location: NJ

    YotaTruck Junior Member

    Like I said I kind of figured...but anyway, take a look at this:

    http://www.monsterscooterparts.com/49enwimapust.html

    Weedeater engines seem to top out at 35cc, and I've always wondered about slightly larger two strokes. I was wandering through Harbor Freight on my lunch hour and came across their post hole auger, which uses this same motor-a 1.5HP @ 6500 RPM two stroke. If you look at the bolt holes on the clutch bell, they look like you could bolt a standard weedeater shaft and housing right on there. Just a thought. It looks like the cheapest they can be had for online is about $125 plus shipping.
     
  8. Erich_870
    Joined: Feb 2009
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    Location: Juneau, Alaska

    Erich_870 Junior Member

    Both would be good candidates.

    The trick is finding a prop that matches the RPM and torque curve of the motor. Ideally you find one that allows the motor to turn at it's peak power.

    Building a set up that has a gear reduction is probably the most effective way. You can play with the gear or pulley sizes until you find the right combo. This then leads to a more complicated build and requires some better fabrication skills, so not many have tackled it.

    Erich
     
  9. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

  10. HelicopterJohn
    Joined: May 2012
    Posts: 80
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    Location: Seffner, Florida

    HelicopterJohn HelicopterJohn

    Where have I been?

    Man I can hardly believe it but my long tailed Mud Motor Mania Part I has been my most popular youtube success with over 274,000 views. https://www.youtube.com/watch?v=haw-QuCNty0
    My next most popular video is Mud Motor Mania Part 2 with over 77,000 views. https://www.youtube.com/watch?v=BXBAbt3V8wA
    All I can say is people must really like mud motors. Ha Ha

    Well, it has been quite a while since I posted so I will give you an update on my boating adventures.

    I sold the ole John Boat shown in the above videos and also sold the Honda GX35 long tail mud motor to a fishing guide in Canada.

    I know this has nothing to do with weed eater conversions but actually leads back to the subject.

    I purchased a used NuCanoe Frontier 12 Fishing Kayak that had an ole 5 speed trolling motor on it for power. You can check out all the videos I have done by checking in on my youtube channel https://www.youtube.com/channel/UCSue4W8frKuFP29flja5aBA

    You can also see what I have been up to by visiting the NuCanoe Forum Rigging & Outfitting Section
    http://www.nucanoe.com/forum/outfitting/

    I have made many modifications to my NuCanoe Frontier 12 fishing kayak most of which have concentrated on steering and propulsion. Here is a brief list of what I have done.

    1. Replaced the Minn Kota 5 speed trolling motor with a new Minn Kota Riptide 55# thrust variable speed trolling motor.

    2. Designed a foot pedal manual steering system for the transom mount Minn Kota trolling motor.

    3. Designed an electric steering system for the Minn Kota transom mount trolling motor based on a Ken Simpson original design.

    4. My own design on an electric steering system for the Minn Kota transom mount trolling motor utilizing a linear actuator.

    5. My latest steering system design the allows for either manual or electric steering options and also tilt and trim options.

    6. Currently working on a conversion of Minn Kota 5 speed motor to variable speed which utilizes less amperage thus longer run times on the motor. Not there yet but it does show some promise.

    7. Have made several other items like my transom motor mount plate for the NuCanoes.

    Basically, having a great time kayak fishing and designing modifications to make a nice kayak even better.

    BACK TO WEEDEATER CONVERSIONS

    The thing that has always been in the back of my mind was to utilize one of those Honda GX35 motors like I used on my long tail mud motor to power my NuCanoe and other Fishing Kayaks. I want to utilize a vertical shaft with a gear box at the bottom for prop attachment. My goal would be to utilize my latest steering control system to steer the GX35 outboard like I have successfully done with the Minn Kota Trolling motors. The nice thing about utilizing my steering system and going to a vertical shaft instead of the long tail design is that it could be easily steered (i.e. making tight turns in either direction) from the seated position without a tiller handle. Also, the Honda GX35 starts very easy and a extended pull start rope could be easily installed. Furthermore, a remote kill switch could easily be added.

    I keep thinking that if that GX35 was able to push the John Boat that also had a 4 HP Mercury Outboard attached along with a trolling motor and battery at 3.5 MPH it should push my Kayak along rather nicely. Now I wish I hadn't sold the GX35 setup. Ha Ha

    John
     

    Attached Files:

  11. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    Hey, John. It is good to hear from you again. I like the above pics you posted.
     
  12. HelicopterJohn
    Joined: May 2012
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    Location: Seffner, Florida

    HelicopterJohn HelicopterJohn

    Hi,

    Yes, I have been having a ton of fun using my kayak for fishing.

    John
     
  13. Jim Caldwell
    Joined: Aug 2013
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    Location: Cleveland, Ohio

    Jim Caldwell Senior Member

    Why not just hang the 4 HP out board on the back?
     
  14. HelicopterJohn
    Joined: May 2012
    Posts: 80
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    Location: Seffner, Florida

    HelicopterJohn HelicopterJohn

    Honda GX35 DIY Outboard for Kayaks

    Hi Jim,

    Thanks for your valued input.

    Wish it was that easy. I have a real nice Mercury 4 hp 2 cycle outboard that would clamp on.

    The manufacturers recommend that you limit the outboard to 2.5 hp. which are considerably lighter than the 4 hp.

    One thing that I am looking at is trying to get a lower end gearbox that will work in salt water conditions and has the right gear ratio and is reasonably priced. Probably too much to ask!!!! Ha Ha

    If anyone has any ideas on this I would really appreciate any input.

    This would be a really fun project.:):):)

    John
     

  15. Cornholio
    Joined: May 2016
    Posts: 1
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    Location: Auckland

    Cornholio New Member

    Quote please

    I am in new zealand needing a prop kit for a stihl weed wacker dude. Natorvations@gmail.com
     
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