I have a 3/16 flex shaft for my 31 cc engine that I'm putting in my boat. I became aware that there may be a possibility that this would shear under torque and that I NEEDED to get the 1/4 shaft instead. I'm hoping this isnt true and the 3/16 will work because I already have my strut and flex shaft in 3/16. Any advice would be great. thanks

Hi,
You can use the 3/16 cable until it breaks, you can be pretty sure of that. The 1/4 is the industry standard because of its strength The 1/4 cable has been used almost since the inception of gas engines. Most new guys go and get stuff because it is cheap/handy. So you know you are not alone. Maybe you can drill out the strut if there is enough meat in it.
A source of new 3/16 stainless steel cables i is from a speedp repair shop just be sure it is a left lay, they will crush a square drive on the end if required.
Hope this helps.

Are you sure the actual cable is 3/16"? Were you measuring the round part of the cable or the squared end ? I just measured a 1/4" cable and it has a 3/16" square end.I have 31 and 32 cc weedeaters and all have a 1/4 " flex cable.

I'm going to use the weedwacker'shaft, which is 1/4''. I just have to buy a new strut/stinger now...

Thanks again for everyones help!

Here's something you might consider before buying new hardware,although I don't know what prop size choices you might have with the 3/16" prop shaft.
www.aeromarinerc.com/index.php...emart&Itemid=53

You can buy a sleave that goes into a 1/4" prop hub to make it a 3/16", Hyperformance props (the old Prahter molds) sell there props with the sleave included.