Weed eater engine conversion

[wac m trac m]

Those are some cool ideas Orphan cb. I see the office chair wheel bracket thing. Are those gun scope rings? Great job man.


John you've taken it to another level. Looks cool. I didn't think you needed gear reduction though those 50 cc moters top out at a lower rpm right?
Well you know better then me. I'm really curious how it does. Good luck.

[John O`Neal]

Wac m ; You are correct, the 52cc motors make max torque at around 5500 rpm. They produce enough torque to utilize the smaller Young`s props without a gear reducer. They work great in a direct drive format and are simple to build. The gear reduction model is just a venture to see that if by multiplying the torque available several times, through the gear reducer, that I could then utilize a much larger prop. The desired goal is to produce greatly increased thrust and some mud slinging ability.

[Orphanedcowboy]

Originally Posted by wac m trac m

Those are some cool ideas Orphan cb. I see the office chair wheel bracket thing. Are those gun scope rings? Great job man.

They are 1" split shaft lock collars:





They are about $3 each at Ace Hardware. I just ground them flat on one side to make mounting them easier.

On a side note, I found 3/4" od x 3/8" id and 3/4" od x 5/16" id sintered bushings for less than $3 each and the corresponding seals for less than $4 each at Motion Industries. You can order online and they will be at your door in less than 3 days.

Motion Industries

I have completely scraped my plans in favor of Turn4Fun/Ripped Off design.

There is a local company that has the aluminum tube and stainless shaft, deliverable by UPS anywhere in up to 6' lengths.

Discount Steel

I bought enough material, since they were local to me, to build 6 shafts with tillers for $107, they charge a $2 per cut fee for odd size cuts, so I had them just cut everything in 12' lengths. I have one complete shaft in the books and working on a second, waiting on props.

One question, what are y'all using for a thrust washer/bearing?

I put a collared sintered bushing in the prop end of the tube, with a 1/4" thick 1" diameter teflon washer riding between the bushing and prop. I have my lock collar on the engine side to keep my shaft in the engine, but using a trolling motor prop I noticed the thrust created a potential problem.

I also created a clutch lock out using 2 1/2" aluminum bar, cut down to 2.375" x 1/2" thick with 3/8"x 24 tpi center, threaded directly onto the Ryobi crankshaft. I used 3/16" roll pins in 2 places to connect the crank with the flywheel.

I have been taking alot of pictures, so I'll post a slide show when I am done. The Turn/4Fun/Ripped Off design is the best I have seen, commercial or otherwise, very easy to follow instructions.

I also ordered some 1 1/4" and 3/4" diameter teflon rod for another experiment using his plans.




John, have you had a chance to try out the props? Also, what type of shaft does the Duro Power engines come with? Splined or square?

[John O`Neal]

Cowboy; The props arrived today. I probably won`t have a chance to test till sometime next week. The Duropower brushcutter units utilize a hardened steel shaft which is splined at both ends. The OD is .314.

[Orphanedcowboy]

How are you making the connection, welding?

[John O`Neal]

Cowboy; I assume you are referencing the prop to shaft connection on the duropower units. The Youngs props with a 5/16 id mounting hole T-4 , T-8 or T-12 will slip right on the Duropower shaft with the gearhead removed . I use a cobalt bit and a centering jig to drill the hardened shaft.

[ben2go]

Originally Posted by John O`Neal

Cowboy; I assume you are referencing the prop to shaft connection on the duropower units. The Youngs props with a 5/16 id mounting hole T-4 , T-8 or T-12 will slip right on the Duropower shaft with the gearhead removed . I use a cobalt bit and a centering jig to drill the hardened shaft.

Holding the prop in place with a roll pin?

[John O`Neal]

Ben2go; Yes to the roll pin method. The T-12 installs in a more conventional manner (ie) The back of the prop is slotted to slide over the roll pin which then acts only as a shear pin. The prop is then held in place by threading the shaft and installing a nut, or by drilling the shaft and using a cotter pin to hold the prop over the pin. There is a pic of that method in an earlier post.

[wac m trac m]

I like that T 12 design. I think if you hit a rock it might give a bit. The roll pin does not. Thats how I broke my shaft. I had a solid 3/8 ss shaft and it snapped at the moter end where I squared it up to only 1/4 inch to fit my briggs moter. My clutch is still in there and doing well but I found out I can buy a new one for 16 bucks if I need it.

I'm getting pretty hyped up. We are still in a drought here in central TX. I found a nasty shallow mudflat that is ate up with teal. Our early teal season opens in 2 weeks. Cant wait to use my little set up to putt in there on the shallow flat. Today I'm building a blind for my Steath. It's going to be a slaughter...cant wait.

[Orphanedcowboy]

Originally Posted by ben2go

Holding the prop in place with a roll pin?

No different than the majority of trolling motors:



You would be surprised at how strong the roll pin method is.

[ben2go]

Originally Posted by Orphanedcowboy

No different than the majority of trolling motors:



You would be surprised at how strong the roll pin method is.

I have that set up on a 3HP Minn Kota trolling motor.

[Orphanedcowboy]

Originally Posted by wac m trac m

Those are some cool ideas Orphan cb. I see the office chair wheel bracket thing. Are those gun scope rings? Great job man.


John you've taken it to another level. Looks cool. I didn't think you needed gear reduction though those 50 cc motors top out at a lower rpm right?
Well you know better then me. I'm really curious how it does. Good luck.

I need to clarify, the swivel caster is available in several styles:

Threaded Stem Swivel Caster:



Plate Swivel Caster:



I used the threaded stem because I made a motor plate, but you could use either style, the plated could be bolted straight to the deck of a small bolt with proper reinforcement.

[wac m trac m]

I'm going to try making a mount like yours. I bet with the 2 rings it wont slip.

I got my shaft back finally and i noticed it's a little bent. If I roll it on a flat surface it wobbles a bit.

Yall think it's not worth using? I straightened it a bit but it does wobble. I'm using ripped offs design so there are bushings in the middle and both ends.

[ben2go]

Originally Posted by wac m trac m

I'm going to try making a mount like yours. I bet with the 2 rings it wont slip.

I got my shaft back finally and i noticed it's a little bent. If I roll it on a flat surface it wobbles a bit.

Yall think it's not worth using? I straightened it a bit but it does wobble. I'm using ripped offs design so there are bushings in the middle and both ends.

Is it possible to put a bearing/bushing close to the center of the shaft.That would support it and eliminate the wobble.

[Mark Wo]

Use an oarlock. On the duropower unit the oarlock fits perfectly over the spot where the clutch housing meets the driveshaft. Tighten one nut and you have a mount that turns from left to right and moves up and down. Purchase the appropriate sized oar lock bracket (part that mounts to boat) and you have a pin from the oarlock that drops right into the bracket you can screw onto your transom or any motor mount you devise. Easy easy easy.

Here is the oarlock and bracket types to use