My Mariner 150 is the same way. I wouldn't recommend trimming it up because without water to cool it, damage can occur very quickly. A few suggestions:

Make sure your battery is a "cranking amp" battery NOT a regular deep cycle.

Make sure your "cranking amp" battery has more than 1,000 marine cold cranking amps.

Buy some cups to feed water to your cooling unit and start the battery at home first.

And for emergencies, carry jumper cables in your boat in case you need to borrow power from your trolling batteries.