Weed eater engine conversion

[PAINTBALLER1244]

Hey Guys I Have Successfully Made One Of These,if Anyone Wants Pics I Can Sent Them To You Ro Tell You How I Did It.

[sonycrayfish]

Send it to me!

Sonycrayfish@yahoo.com.com

[PAINTBALLER1244]

sure here they are,its a boldens 31cc

[ripped off]

Looks good. I used a similar homemade prop at one time and it worked OK, but not as well as the ones I use now. If you want to try one out I'll PM you with a link to my source.

[PAINTBALLER1244]

yes,please that would be gr8,im always open for ideas to improve design

[DaveH1]

Welcome back Ripped Off!!

Glad to see you hadn't disappeared from the Internet.

How'd duck season go for you?

Can you PM me your prop source?

What size of drive shaft do you use inside the aluminum tube? What seals and bearings do you use to support it?

Thanks,

dave

[PAINTBALLER1244]

Actually There Is 4 Sealed Bearings In The Bottom But I Still Packed Marine Grease In It Intil It Came Out The Sides,theres 2 Pinion Shafts In The Bottom And Ther Is 2 Bearings On Each There About 1 Inch In Diameter,i Am Still Interested In The Prop Link You
Have.

[PAINTBALLER1244]

Oh Yeah The Shaft I Believe I Made From A 3/16 Rod,steel

[kengrome]

Originally Posted by ripped off

Looks good. I used a similar homemade prop at one time and it worked OK, but not as well as the ones I use now. If you want to try one out I'll PM you with a link to my source.

I would like to try your source if you're willing to post it or email it to me, thanks!

[PAINTBALLER1244]

acually i did it all myself and made all my own part to make it work,i could tell you everything i used if it helps?

[ripped off]

OK, I intentionally neglected posting or replying to emails on this for the last few months because I'm a firm beliver in letting people figure things out for themselves. I figured that posting teaser pics of a successful modle with no directions would spark folks to tap into their creativity and start experimenting rather than assembeling pieces from a parts list. Appearantly there are more people on here that prefer the latter rather than the former. KUDOS to those of you who did take the leap and come up with working designs of your own. Heres how mine are built.

Materials list:

* 5' length of 1.00" x 0.125" wall aluminum tube (drive tube)
* 5' length of 3/8" stainless steel round rod (drive shaft)
* 4' length of 7/8" x 1/16" wall aluminum tube (handle)
* 15" x 4" of 0.10" aluminum flat (for skeg, will make 2)
* 2" x 4" x 1" thick aluminum flat bar (universal mount)
* 3 bronze plain bearings, 3/8" I.D. x 1/2" O.D.
* 3 bronze plain bearings 1/2" I.D. x 3/4" O.D.
* 1- 3/8" shaft collar
* 3 oil seals, National/ Federal-Mogul brand #330385 (got them at O'reilly)
* 3 Stainless 10-32 x 1/4" cap screws and nuts (bearing set screws)
* T-10 prop from www.Youngprops.com
* 30 cc or larger weedwacker powerhead
* Handelbar mounting bracket for a Stihl brush trimmer





First lets start with the powerhead. Choose one that is at least 30 cc, and one that will mount to the shaft independent of the throttle grip. I also recomend that you bypass the clutch if present. Belive me, I melted the plastic housing on the trial run with my first prototype when the clutch slipped under load.

This is what I use http://i82.photobucket.com/albums/j2...n/000_0270.jpg

About the bronze bushings; the smaller ones nestle inside the larger ones. When you go to the hardware store to get them you will notice that some will fit insde each other very easily and others won't. Sort through them and select ones that won't quite nestle. You will press them together with a vise or C clamp. Next use a 3/8" nut and bolt as an arbor and chuck each bushing in a drill or a lathe. With the drill running, work the outside down with emery cloth or a fine file until they will slip easily into the drive tube.

Cut the drive tube to be 1 1/4" shorter than the driveshaft.

Drill and tap a 10-32 hole for a set screw at each bearing location, one in the center and one near each end.

Cut the skeg plate corner to corner and file it to your desired shape, and have it welded to the drive tube.

Insert the bearings and secure them with the set screws. On the prop side, insert the bearing 1/2" below flush. On the engine side, 2" below flush.

Grind 1 1/2" of the driveshaft square to fit the engine's output shaft. Do this as precisely as possible. Any machine shop could do this pretty reasonable.

Secure the shaft collar about 3/8" below the squared off end. You may need to file the outside of the collar down a bit so it does not rub on the inside of the drive tube. The collar sits on top of the upper bearing and you'll want to adjust it so the square end of the driveshaft is flush with the end of the tube.

Press two of the oil seals into the prop end of the drive tube. Fill it with some gear oil or marine grease and insert the shaft, then install the upper oil seal.

Fabricate the tiller handle from the 7/8" tube (bend or cut and weld to desired configuration). Mount the tiller to the drive with the handelbar mounting block. Heres a pic of the mount.

http://i82.photobucket.com/albums/j2...n/000_0269.jpg

Add the throttle grip to the end of the tiller and rig up a longer cable.

Here are some pics of my universal mount. I built this entierly with a hacksaw, files and a drill press, but a maching shop could probably whip one out for you for next to nothing.

http://i82.photobucket.com/albums/j2...n/000_0267.jpg
http://i82.photobucket.com/albums/j2...n/000_0266.jpg
http://i82.photobucket.com/albums/j2...n/000_0268.jpg

This mount piviots forward unrestricted but is limited on how far back it will tip (this is to set the drive angle) and will rotate 360 degrees. The pin on the bottom is merely a 1/2" bolt with the head cut off, and is threaded into the bottom of the mount. On the boat you will need to mount the female half of a standard oar lock. In the side view you can see a slight angle on the bottom right hand side of the upper half of the universal mount. The more angle you file here, the farther back the drive will tilt. I recomend that you start with no angle at all and file a little at at time until you get the drive angled the way you want. I recomend as shallow a drive angle as possible without the prop cavitating.

Install the prop and the powerhead and you're good to go.

You will need to note that because weedwackers run at such high RPM, you will get the best performance at about 1/3 throttle. Any more than that and the thrust drops off and motor starts to bog.

Heres some more pics

http://i82.photobucket.com/albums/j2.../motorside.jpg
http://i82.photobucket.com/albums/j2.../motorrear.jpg

Note also, if you are building a "lower unit" style like Paintballer's, the prop will turn the opposite direction as the engine. I recomend the T-8 or the T-13. If you are building a straight shaft where the prop turns the same direction as the engine, I recomend the T-10.

[TerryKing]

Have you guys seen this "weedeater" design from Thailand??

[mrmoto58]

Hi your weed eater idea looks great .my son needs a small motor .thanks Ted . p.s. if you had more lower units to fit weed eater motors you could sell them on ebay .

[spyderpaintball]

ripped off, thank you for the detailed post. I have a question about the bearing set screws. how would those work? do you just put the screw straight through the drive housing to keep the bearing from sliding down? wouldnt it hit the drive shaft? would greatly aprechiate an explanation for these set screws and maybe some pictures. thanks

[TerryKing]

Here's a PDF of RippedOff's post:
http://www.terryking.us/boating/Ripp...eedwhacker.pdf

I wanted to be able to see the photos and stuff together in the shop....

RippedOff, if you don't want this up there, let me know and I'll shoot it with my 10 Gauge Parker :-)