[oil pan 4]

The surflo pumps warn against giving them reduced voltage.
I was simply going to use a bass boat live well pump cycler.
These timers are built specifically to cycle small 12 pumps like this on and off to keep your catch or your bate alive and your boats battery from getting drained.
What this battery saving pump timer does is turn on the air or water circulating pump to a boats live well for 30 seconds, then it cycles off for a selectable time any where from a few seconds up to 5 minutes.
The contacts are rated for 10 amps, my surflo running under almost no pressure draws about 2 amps.
Since this little project is coming along so well I went ahead and ordered one last night. It was only $35 with shipping.

I also noticed my little cooler can become really full of spent ice, so full that I don't really see how I will be able to dump it with out unhooking everything from it.
I could just scoop out the water with a cup, if there wasn't several inches of ice on top.
Since I am going to run water injection it would make more sense to be able to pump that water into the water injection tank. So I think I will install a 3-way solenoid valve to the send the return water back out through a dump port.