How to disable automatic fsck checks

First, to see the parameters of the checks, you can use:
tune2fs -l /dev/sda1
Then, if you would like to change them:
tune2fs -c 0 /dev/sda1
would disable the checks on maximum count number (for example, on my computer, fsck makes automatic check after 5 reboots).
You can increase the number to say 25 reboots:
tune2fs -c 25 /dev/sda1
Or you can alternatively, set a time limits for reboots using the -i option instead. For example, typing
tune2fs -c 0 -i 0 /dev/sda1
would turn off the checks completely.
For more info, check man tune2fs.