[greglepore]

What machine? There's nothing inside to tweek, although there are easily replaceable parts if they break. On some machines you can get different temp thermostats (expressoparts.com) but really no need. Two thermoswitches, a vibratory pump, a thermofuse, and some wiring and a steam valve

If you sprayed coffee, you either didn't have the pf seated tightly, opened it too early after brewing or had the button engaged too long-you need to tr it off aft 5-10 seconds then begin your pull. May not be necesssary if you're already in high 180's-190. It could also be that your machine uses a thermoblock rather than a small boiler; these heat/cool more rapidly and hold less water, which is why they're undesireable.