Weed eater engine conversion

Well it was in the rejects bin at K mart for $50 brand new but no cutter head ..so I thought I would see what all the fuss was about .....mount a prop on the shaft ..start it up ..stick it in the swimming pool and see if it stalls and how hard it pushes ..might make a spare or auxilary for my new boat .

 

Or it could make a great boat anchor if it doesn't work as we all know it can.

Missed the American dig....

Mark

 

This thread is amazing. I've been reading it over and over. Tons of great ideas. Does anyone know what happened with the parts from Thailand ( cast aluminum coupling)etc? Is the a source to buy these aside from the complete kit? I just recently purchase a Kiwi Angler kayak and plan on going with the 52cc motor and 5:1 scooter trans and making a sealed bearing drive tube in the mud motor fashion. The river I mostly plan on using it on has a decent current and about a 4 mile stretch between launch sites. I plan on drift fishing to some great spots and being able to motor upriver to my launch with out having to involve anybody else parking a car down river. Here are a few pics of the kayak and transom area. Any ideas would be great. Thanks to all for the posts. It has been a great read.

 

you may not have suffieient speed with a weedwacker motor to overcome the 4 mph current....you need something capable of 8 mph and I dont think I have seen a 52cc do that speed ..try a 100cc four stroke maybe ...

 

My main goal is to be able to have enough thrust to go back upriver. I'm torn between getting the reduction trans and fabricating a holder for the drive tube or going with the honda clutch assembly with out the reduction. The kayak is 12ft long 36 inches wide and weighs 65lbs,myself 175lbs and I estimate with all gear about 270lbs. I not quite sure how well it will turn by swinging a mud motor or if it would be better to keep the motor in a fixed position and make some sort of rudder system to steer since no "v" hull. Another issue on either setup is what has been the best way a 3/8 drive shaft would mate to the honda clutch or the scooter trans. I looked back over the thread and swore I seen it somewhere but can't seem to locate it. Sorry for all the questions. I'd just like to have some confidence in my parts list before buying and trying things that don't end up working. Moneys tight hence the kayak and no boat but I think after its all up and running there will be no looking back. Thanks for any help you can provide.

 

gearing will not help your speed it will only make matching a propeller less critical ....Power is what drives your boat and 8mph is not possible with a wacker ( 4mph + 4mph current) ..go for the 100cc its light enough and the motors are cheap on e bay etc direct drive will be fine ..straight shaft no universal joint ..look for lifan brand or similar

 

pistnbroke- The transom is rated at 40lb thrust. It just has a 2x8 bolted in between what looks to be 1/8 inch poly resin. The kayak is rated to 400lbs so I have some room to work with on engine weight but also know the plan is to be able to lug everything around a portage if need be. I'm in southeast Michigan about a half mile from the Huron river. I'm surrounded by about 6-7 metro parks with launches all on that river so I need to find out what the flow averages are. I might be over estimating the current. The river goes from 6 inches to 14 ft but overall 1-3ft mostly.The area right behind the seat is meant for a cooler or gear but can probably be made to hold a platform for a bigger motor.

 

you dont need a platform only a piviot pin....go back through the posts and copy all the photos you like ( right click) to your computer then you can study them without searching this very long post...steve

 

Thanks for the tip. Yeah I've spent days after a 4 hour complete read looking back over posts only to get side tracked from what I was trying to find. Saving the pics will be the way to go. So many ideas and trials going on ya get hooked on following the progress. Hopefully mine will start soon. Just checked ebay and seen the lifans from 2.5 hp on up and a 97 cc pit bike motor from Monster scooters. Seems as if when I've got it narrowed down I derail myself.Thanks again for the tip.

 

You'll make it

I hunt similar streams where the current is 4 mp or more and the 52 cc motor has no problem making it back upstreams. None whatesoever.

With no current the 52 cc motor pushes the boat 6.2 mph. That is approximately the hull speed of boat. Going back upstream, the boat still goes around 6 mph. Hull speed has to do with the speed at which the boat will travel without getting on plane, it isn't a subtraction from the current going against the boat. Stream speed subtracted from hull speed is not what you are going to get with this motor. At least it wasn't in my case.

Mark

 

Mark Wo- Thanks for the reply. I was also thinking since its not a "V" hull and rides just on the pontoons it might help. Its supposed to have a 3.5 inch draft. Haven't even had it in the water yet. Hopefully wednesday to check things out. I'll be able to see what paddling will do against the current to get an idea. Either way a motors getting built. which one? Still figuring that one out.

 

What would happen if you had a 1:1 ratio?

 

you have more prop revs but less torque....the faster the prop runs the more inefficient it is ...the more toque you have , through gearing ,the easier it is to turn the prop so its easier to find one that loads the motor...the thai long tails all have gearing but that does no mean a one to one will not work fine.. plastic props flex as the rpm goes up ,reducing pitch (and motor torque drops) giving a variable pitch effect which helps the motor keep going

 

Harbor Freight 2 1/2 hp 79cc engine 3600 rpm?

Just wondering has anyone tried or have an opinion on this motor for use in a
no clutch system. Cannot find the weight of the engine anywhere. With a coupon the engine works out to be about $110. Would really like to use a model like this but with a clutch.I know there's a mini bike clutch that will fit but unsure on what the options would be to make a cover with carrier tube for the drive shaft.Any ideas?

Thanks Tom

 

as you get towards the 100 cc capacity they get easier to prop and hence the need for a clutch less inportant ...photo does not show the output see its 5/8 dia

The 6.5 hp is on sale at $99 god thats cheap