Cure for loose servo horn screw?

I am having a problem keeping the winch arm tight on the winch servo (Hitec 715) because the screw keeps getting loose, so the arm will slip a spline and you can’t pull the sails in as tight. If I tighten the screw, it “feels” tight, but obviously doesn’t hold the arm on tight enough.

know the arm shouldn’t slip because of the splines, but it does. The geartrain looks good, and doesn’t slip.

Any other reason the arm might slip a spline?


Does your screw back out? In other words is it loose when you open up the boat to look at it after the arm has slipped? If it is loose, you might want to try some loc-tite or some other goo to lock down the threads. you could also try a slightly larger screw (there are some metric sizes that convieniently happen to be slightly larger than many standard english sizes).

If the screw is still tight, then I think your splines have worn down. I have heard of this happening to several people with this model winch. Is the male spline made of metal or nylon. If it is nylon, then most likely it has worn down and that is what is causing the slippage. I’m not sure if there is a cure. I use Futaba winches and they all have metal splines. Never had a problem with them…

  • Will

Will Gorgen

Tomo, Check that the base of the winch arm is not cracked. If it is made of plastic it is hard to see, but when the pressure goes on it opens up and jumps a spline. [:-banghead]

Do it NOW before it`s too late.

I’ll also check to see if I have a spare round output wheel. Maybe just swapping in a new one will thighten tings.

I think what is actually happening is that the screw is being pulled out (not turning). The winch arm is be flexing and trying to pop off, and pulling the screw out, so the hole in the output gear is getting chewed out- bigger. That means I’ll need a servo with a metal output gear or just a new plastic gear, as I don’t think it can be repaired, and loc-tite won’t bond to the plastic.

Can you get a metal output gear for the HS-715 servo? How about replacement gears? I would prefer to stay with that servo.