Quoted from Rob_G:

I replied before in one of the other threads, but here it is again. You can adjust the jaw height a bit by adjusting the following screw on the mechanism under the playfield. Loosen the nut and then turn the threaded shaft. Don't adjust it too much though..
It's strange because usually the problem with the jaw is that it's too high. I had to remount the entire snake assembly on washers for my game to level the jaw...
Rob

Quoted from j_m_:

the adjustment is under the playfield. when viewed from underneath, this assembly is slightly to the right and forward (towards the front of the machine)
the arm on the image that Rob_G supplied above is the one that connects to the lower snake jaw and held in place with an E-clip
you shouldn't have to remove anything to make the adjustment
if you haven't figured it out in the next 9 hours, I'll take a photo when I get home and upload it

Quoted from j_m_:

how do you loosen a washer? the picture shows a nut with a built-in lock washer. the nut hold the bolt with the rubber stopper in a specific place.
I believe what you need to do is loosen the nut so that you can either back off the bolt or screw it in a bit further (depending on whether you're trying to raise or lower the snake jaw) and then tightened the nut back up to re-secure the position of the rubber stopper

Quoted from j_m_:

I'm busy building run-dmd clocks this week but I'll see if I can take photos this weekend if someone else hasn't stepped in to help