How Do I Make My Small Engine Whisper Quiet?

I am doing an outdoor grow this season and I have decided to use an auto-watering setup with timers and all of that good stuff.

Anyway, I am using large agricultural tanks for the water supply and the only way I can fill the tanks is with another tank. The fastest way to do this is with a gas-powered water pump with suction and discharge hoses. The one I have pumps 150 gallons per minute. That should be enough volume to make the job a fast one but I am still concerned about noise.

Can you think of a way to make it so that the engine is only as loud as an average sedan? Maybe not by doing something to the unit itself but by building a sound deadening enclosure for it? Have any of you guys done this?

If I am able to completely fill the tanks (220 gallons a piece) I should be able to set the timers on them and leave them unattended for up to a month at a time. I REALLY want to make this work. I thought about just attaching a hose to the tank drain and draining one tank into another but I'm not sure there would be enough pressure for the tank to drain completely into the other one. Please advise.

how good can you fabricate? exhaust running into a bucket of water (on a gasoline style pump) like a bong type setup as long as it was leek free would b as quiet as you could get it with out building a sound proof enclosure for the pump motor. if you were to utilize both you could easily be quieter then the average gust of wind... depending on equipment and brain cell capacity

go to you local hardwear store and pick up a eletric water transfer pump should run about $88. splice the cord and conect to you car battery

as long as the one tank is higher thatn the other on it will drain i like the exhaust into water idea and dig a hole for the pump to sit in that would be as quite at you could get

Cool guys, thanks. I'll check into it. Some of my friends are pretty good at this stuff so I'll ask them for some help. Without telling them what it is for, of course.