Someone help me out with this weedeater propulsion?

Hi all. Recently picked up (what I reckon) to be a great motor for a weedeater conversion. It's a 30cc straight shaft ryobi trimmer. I have gotten it all planed out to mount to my 14' kayak however I'm confused at how to mount a prop on the end of the shaft mainly because all the nuts and bolts are reverse threaded, and it seems that after I flipped the drive shaft upside down it spins clockwise, whereas most smalls props I've seen are for counter clockwise rotation. If someone could point me in the right direction as to where to get a prop and what modifications I will need to do I will GREATLY appreciate it!!

 

Have you checked this thread?:
http://www.boatdesign.net/forums/diy-marinizing/weed-eater-engine-conversion-1681.html

 

Yes I have. My new plan is to put a hole through the hollow drilled 3/8 shaft to accommodate for a prop pin (I have the young t-13 prop in mind, anythoughts). Any ideas?

 

That is outside my level of knowledge. Hopefully one of the weedeater guys will see this question and have an answer. If you had asked it their they probably would have already seen it.

 

I responded to your email, but a T-13 or T-8 is what you want. I'm running a T-8 and it works, but the motor is pretty bogged down. I'm thinking i need to reduce the size of the blades slightly, but I'm not looking forward to that.

Erich

 

Thanks Erich. Do you see any negative side effects of leaving the 3/8 shaft un cut? Thinking in the future should I need a new prop or anything like that. Edit: I'm also going to be using both of the shafts due to the design of the kayak and shallow waters I will be in. Do you see any problems with this design? I'm worried the shaft might bend?

 

I don't think leaving the 3/8" shaft long hurts anything. My gear head is for the brush cutter model so it has 3 tabs where the guard attached. I need to cut those off as I'm pretty sure they create measurable drag.

About using both shafts, I don't think they will bend, but most guys who build a long tail don't use the gear head as it won't aim properly in the water and you'll loose a lot of the props thrust.

Erich