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 and installing Grease alimite Zerk fittings

    Hey John,

    Need some of your technical knowledge, now that you have already installed your grease fittings on the drive-shaft tube.

    I Need to know what size drill you used, and what thread tap you used preparing to install your grease fittings if possible.

    I got my tubing and stainless drive-shaft from Metals Depot in Winchester Kentucky yesterday. Both in 6' lengths, only cost me $44.20, including shipping. Unfortunately, the 3/8" stainless drive-shaft rod was bent in shipping. I called Metals Depot (859-745-2650) this afternoon, and talked to Brenda. To their credit, they are shipping me another 3/8" SS rod at no charge, and I already received the tracking number! These are nice people to deal with, and their price is very competitive. This is quality material...1" OD x .125 wall thickness x .750 ID 6061-T6 aluminum tubing, and 3/8" diameter 304 Stainless Steel drive-shaft rod material. I will do business with them again. Good source for anyone that needs to buy prop shaft materials.

    Thanks to all the tips from posters on this site... especially Helicopter John. Man! That guy is a dynamo!
     
  2. HelicopterJohn
    Joined: May 2012
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    Location: Seffner, Florida

    HelicopterJohn HelicopterJohn

    Bushing Installation Help

    Hi Chuck,

    The grease fittings I purchased had a 1/4 X 28 thread on them. The recommended drill for this thread is a #3 drill bit which is .2130 diameter.

    I had access to a Bridgeport Milling Machine so I was able to accurately center each part prior to drilling each piece.

    One option that may work if you have a drill press is to find the center as best you can on the 1" O.D. tubing and drill a hole all the way through with the #3 drill bit that is later used for tapping your 1/4 X 28 threads. I would properly clamp the O.D. tubing in the drill press do each drill bushing installation one at a time without removing the O.D. tube from the drill press to maintain proper alignment.Then take a Sharpie or other marking devise and mark the center of each of the bushings that you want to use in your build. I would mark them with a line all the way around the bushing at (mid point 1/2 inch) on the 1 inch length and number them 1,2,&3 so you don't get them mixed up. Then I would insert them one at a time into the tube at the appropriate location and drill through the bushing with the same #3 drill prior to removing them from the drill press. This will give you proper alignment even if the hole is still slightly off center. Prior to removing it from the drill press I would mark one side of the inner hole of the bushing with a Sharpie to make sure you can reinstall the bushing in the correct orientation. Note: Go slow on the feed through the Sintered Bronze Bushings as they are pretty brittle and can break. This is not a full proof method but may be something you want to try if you don't have any other options.

    Then you can tap both #3 drilled holes of the O.D. Aluminum Tubing with your 1/4 X 28 Tap.

    Once you have the bushing predrilled to the #3 drill size you will need to enlarge the bushing holes using a 15/64 (.2344 diameter) drill bit. They still may require a litle enlargement to allow the grease fittings to seat properly into the holes. You could use a (B drill .2380 diameter), (C drill .2420 diameter) or a (D drill .246 diameter). The tollorances on the tubing can vary so your results could be different. I used a (B drill) and it worked fine for me with just a little slop to allow for alignment of the 3/8" stainless steel drive shaft when the grease fittings are snugged to the O.D. Note: I put some blue loctite on the grease fitting threads during the final installation.

    Hope this is of some help.

    John
     
  3. Mark Wo
    Joined: Dec 2007
    Posts: 143
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    Location: Minnesota

    Mark Wo Senior Member

    Or another way

    John's mehtod is most certainly the way for the guy who has the equipment to do so and his results will be better than this method. For the guy who only has a cordless drill, here is what I did on one of the motors.

    Put the bushings in place where you want them in the drive tube. You can use the driveshaft to keep them in place or not - your choice. Drill through the drivetube and the bushing taking care like John mentions. Carefully remove the drill bit and then tap your hole. Install the grease zert. Repeat on next bushing.

    While not a perfect solution, it does work. I used drill pressses on most builds but did use the cordless on one. Turned out fine.

    Using John's method of drilling the drivetube and bushing seperately I had trouble getting the holes to line up when I inserted the bsushings into the drive tube. I was able to do so but it took a lot of time and much frustration. I guess when you are a retired old fart like John, you have lots of time to tinker. Lucky stiff.

    Mark

    I also know guys who have put the bushing into the drivetube (driveshaft installed) and drill a hole on the opposite side of where the zerk was going to go. They then just screwed in a set screw to hold the bushing in place. Remove the driveshaft and drill zert fitting.
     
  4. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    I guess when you are a retired old fart like John, you have lots of time to tinker.

    Watch your lip you young upstart.
     
  5. Mark Wo
    Joined: Dec 2007
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    Location: Minnesota

    Mark Wo Senior Member

    Can't come soon enough. 5-6 years and I should be able to call it quits. I am envious of folks like John, very envious.

    Mark
     
  6. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

  7. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    I'll probably use my drill press, and a centering device I bought for it, that looks a lot like the top half of this device. This device looks like it would be very handy for those of us involved in aircraft. The biggest down side I see, is that it only allows two sizes of holes. I'm not sure if different sizes of guides are available... but I don't believe I saw any on the ad.

    John has some good equipment, and is very talented in using it...I'm envious! I'm pretty much doing the same build he did, with the Honda GX35 4 stroke that will run upside down. Many thanks to John for his help and pics, and the encouragement he gives the rest of us.
     
  8. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    Thanks for the suggestion Mark. I like this idea also. I may use a combination of different ideas. The last thing I want to do is goof up and drill into my drive shaft! The center bushing is my main concern, and I like John's idea of dealing with it.
     
  9. HelicopterJohn
    Joined: May 2012
    Posts: 80
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    Location: Seffner, Florida

    HelicopterJohn HelicopterJohn

    Thanks for the compliment

    :)

    Shame on you for picking on an old fart like me.

    I was lucky and retired at the ripe ole age of 54. I am 66 now so I guess there is some truth to your statement.:D

    Take my advise and retire as soon as you can. That is when the fun begins. These retired years have been the best for me.

    Recently, I purchased a couple of used Honda 5 HP GC160 engines off broken pressure washers.

    I hope to make some type of Mudd Motor out of them. Stay tuned for more Mudd Motor Mania.

    John
     
  10. Mark Wo
    Joined: Dec 2007
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    Location: Minnesota

    Mark Wo Senior Member

    Clarification

    Only insert the driveshaft into the bushing that is far enough to hold it in place. Then drill through the drivetube and bushing. This is an easy way to do it and line up the holes.

    Once one is done and in place, move to the next one.

    Mark
     
  11. Harshana
    Joined: Jun 2012
    Posts: 7
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    Location: Sri Lanka

    Harshana Junior Member

    My modified bush cutter outboard

    Hi guys,

    When I first got the idea of using a grass cutter as an outboard motor, I googled to see if others have done it. I found this page and this was the inspiration till to the end.


    Full view of the motor
    Boat.jpg


    Close-up of the mount
    Boat2.jpg

    Home made propeller with 4.5" diameter nylon block
    Propeller.jpg

    Robin bush cutter
    IMG-20120617-00097.jpg

    Test run
    IMG-20120617-00096.jpg

    Thank you guys,
    Harshana
     
    1 person likes this.
  12. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    My Modified Brushcutter Outboard Motor

    Good job there Harshana! I'm most impressed with that propeller, that you home brewed out of a 4 1/2" block of nylon! The second thing that comes to mind is, "were you able to outrun that monster storm I see behind you"! Obviously, you must have... because you're here with the pics and post. Good job... congratulations.
     
  13. Harshana
    Joined: Jun 2012
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    Location: Sri Lanka

    Harshana Junior Member

    My Modified Brushcutter Outboard Motor

    Thank you American_Yankee for the encouraging comments. I did my test run in a lagoon and yes it was a stormy day. Therefore I stayed within few hundred meters from land.

    About the propeller, I have more pictures of making it. But unfortunately they are all thumbnail sized (my kids have played with the phone camera and this is what happened). See if you can make anything out of it.


    Mark the blade shape on the block
    Photo-0173.jpg

    Mark the angle on the sides (this will determine the pitch - also the whether its left handed or right handed)
    Photo-0174.jpg

    Cut the blade gaps
    Photo-0175.jpg

    After cutting all blade gaps
    Photo-0176.jpg
    Photo-0177.jpg

    Cut along side the marks
    Photo-0178.jpg
    Photo-0179.jpg

    After removing all large parts
    Photo-0181.jpg

    Then use the hacksaw blade and a chisel to remove the center sections. Finally I used a grinder and a sander to finish. You can shape the blades as required.

    From my experience, 90 degrees is a good angle for blades ie, on the first picture, between start to end of one blade = 90deg.

    Tools I used
    Mainly hacksaw blade for cutting (don't try to use the grinder (or even with cutting blade) for large straight cuts)
    Wise is a must for holding the piece.
    Chisel to remove some of the center areas where hacksaw or grinder cannot be used.
    Grinder to get round / smooth all straight edges and remove some unwanted parts.
    Sander (first with 100grit and then with 320) to get a smooth finish.
    Then the drill to drill a hole in the center.

    When cutting blades (along side - pict 2), make sure to cut to a slight angle, so the base of the blade is slightly thicker than the edges.

    Hope this helps. Let me know if there are queries.

    Thanks,
    Harshana
     
  14. American_Yankee
    Joined: Apr 2012
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    Location: Middle Tennessee

    American_Yankee Junior Member

    Homemade Nylon Propeller

    Thanks for the pics and explanation of how you built your nylon propeller Harshana. That is a good looking prop. Is it safe to say this is not the first propeller that you have built? If it is, you did a great job. I'm thinking a nylon prop, like this, should be very durable. Was the material something you had on hand, or did you have to order it?

    I'm going to copy all of your instructions, and have already saved (and enlarged) your step by step pics. I just might try one of these myself. What do you figure your final cost was for the finished propeller. How was the performance? Thanks for sharing.
     

  15. pistnbroke
    Joined: Jan 2009
    Posts: 1,405
    Likes: 33, Points: 48, Legacy Rep: 404
    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    retired at 55 not soon enough I retired at 45 and got my pension and lump sum ....
     
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