Waterpump soft starter

The problem

The waterpump EK-DCP 4.0 (12V DC Pump)
kept tripping the overcurrent protection on the motherboard.

As neither PWM or DC mode seemed to adress the issue I deviced a softstart by rebuilding an old zalman fanmate.

Initial PCB investigation

Opening the unit shows an easily modifiable pcb.

3 pin with heatsink included

Org. component layout

Org. schematic, I think...

Various components to switch out:
the 7805, pot and res.
I'll be replacing them with an IRF2807, 100k resistor and 470µF cap.

Removing components

Mosfet soldered.

Schematic

What i want it to do

R2 will slowly charge C1, as the voltage slowly increases at the gate
(2.5V and up) it will start to conduct gate to source
wich in turn will slowly ramp the voltage for the pump.

Reroute some traces

Some wires added

Add the cap.

Final