Ok! still having problems with my 40cc drag boat! Originally I ran a straight solid shaft but there was too much down angle and it would bog the nose down bringing it back off the plane. Then I cut the shaft as the clutch runs a spline and drilled it out so I could locktite the flex in and run it out to the strut. Now it keeps letting go (winding the cable out) at the engine end. I only get to idle around to warm up the motor and as soon as I try to give it a bit of go it lets go every time!
Are there any disadvantages if I go back to a solid shaft with a universal joint to minimise the drive angle as it exits the hull ??
I did make sure that the flex etc was very clean before it was locktited but it doesnt seem to help at all!
Any help is greatly appreciated! I am getting very frustrated with this boat!

Cheers,
Chad..

Can't you tap the clutch output end to screw in a collet? Aeromarine sell a bunch of different collets...maybe something could fit? That or possibly weld in a square adaptor and run a square cable? Just throwing ideas... do you have pictures of the clutch/cable assembly we could see?

Here are some pics. hope this helps a bit!
The sold shaft is centre drilled to accept the 1/4 flex in the opposite end to the spline.

I don't know if this would work, but I think I would try soldering the tip of the cable that goes into that shaft to get all braids soldered together and drill/tap the shaft for a setscrew. Otherwise, if you can find a collet that would work you could possible thread the outside diameter of the shaft for the collet to screw onto. Depends on the O.D. of the shaft. There are various threaded collets that might work...Aeromarine has some.

Hi,
This might sound silly but what direction did you thread the clutch?(left or right) Remembering the engine runs anti clockwise(viewed from the rear) when running.

I would check with some of the professional drag race teams. They run carbon fiber drive shafts in their top fuel race cars and they have to use some kind of epoxy to withstand 8,000 horse power.

I havent threaded anything yet, wanted to bond it all together if possible!

Thanks guys! Keep the ideas coming, Im sure there is a solution to this! It doesnt help much when you dont have a dime to spend!lol
One thing for sure is when I do solve this I will post it up in the homebuilders section!!

Cheers,
Chad..

Using a setscrew wouldn't cost much. With the cable end soldered together I think it could work...put 2, one one either side of shaft. I'd give it a shot since it's a homebuild project on a budget.