What did I do wrong?

[HappyOne]

I bought a boat from a member here recently. It is a 25" vee from Head of The River RC. The motor is an Ammo 2300, the ESC is a Turnigy Marine 120A and I hooked up two 2S1P 5000 mah lipos up to it in series. I used the programing card for this esc to set the number of cells to 4 and reduced the motor timing to 7.5 degrees from the factory 15 degrees. I charged the batteries and hooked it all up and set the throttle range as per the instructions. So far so good ....

Then I pulled the trigger and the motor studdered and sparks shot from the ESC

What did I do wrong?

[Rumdog]

Check your series wiring and make sure you did it right.

[HappyOne]

Positive from the esc to the positive on the first battery
Negative from the esc to the negative on the second battery
Negative from the first battery to positive on the second battery

[Boatman]

was it even in the water?

[HappyOne]

Not yet. Just setting it up so when we finally get some decent weather I could get it out for a run.

[Boatman]

doesnt sound like you did anything wrong unless you had two motor connections touching. Other than that you either had or have a bad motor and now or had a loose fet? I imagine you have bad motor and esc now.

[Blackjack-sven]

I've run into this problem before on cars and found that in one instance the motor was shot and in the other the esc was shot. In both cases the motor/esc was running WAY TOO HOT and burned one of the two.

[HappyOne]

Well the ESC is on its way back to Hobby City in HK and I ordered a Hydra 120 from Steve to replace it.

Let's hope that the motor is fine

[Blackjack-sven]

Let's hope that the motor is fine

Do you have another brushless esc you can use to check the motor? Doesn't need to run long or fast, just needs to be smooth through the range.