turn it up on a Cat 3406B
There are 2 allen head screws behind that plate that have 3/8 (on most pumps, 7/16 on others) locknuts on them. Carefully loosen the locknuts with a deep socket, then remove ratchet and insert the allen wrench through the socket so you can hold the locknut in one place. Turn both screws EXACTLY the same amount of turns. Usually start by going 1 full turn on both, then run it. Any additional turns afterwards should be no more than half. Don't get greedy, you'll burn it up. You can get well over 500Hp playing with those B model pumps, but don't come back here blaming me if you don't know how to take your foot out of it and let it cool down. The last B model I had, the screws were turned all the way out, and I hung a C model turbo on it, I was getting a little over 600Hp. But it would get hot, if not careful.