I found the solution to the weak backhoe problem on my brother's L38 in the owners manual page 37. But first I had to search his house to find the manual. The directional valve lever was not in all the way. After pushing it in, the backhoe has plenty of power.
I didn't see the lever at first due to it being blocked by the backhoe platform where you place your feet. To see the directional valve lever, I had to lean way over the platform with the access cover open. The swing lever is easy to see once the access cover is open.
Thanks for everyone's help.
