Hi!

A while ago, I put brushless motor and ESC in my daughter's Zig Zag Racer, and It has run very good and stable with 3-cell li-po. My daughter really enjoyed much faster speed.

Recently, there was lots of water-coming in through the prop shaft tube, even though I thoroughly lubricated with high quality marine grease. Thus, I have replaced the stuffing tube with a little bit bigger diameter tube and a teflon liner in it. Now water does not come in, but I got a problem.

The boat hardly goes straight, even though I keep trimming the streering trim. And when turning, the boat seems to tilt to the turning direction, turning too sharp.

Also when advancing throttle, the boat begins to badly wobble and then spins out at high speed.

Before replacing the stuffing tube, it used to run so stable and nicely, but now all of sudden it goes crazy. My little daughter and I are so frustrated

What causes this issue? If anyone can help my daughter and me, it will be greatly appreciated! Thank you for your attention!

James