Those two pistons are like shock absorbers-not related to any trim system. If you are running on plane and hit a submerged object, these shocks minimize the violent reaction as a result of the impact of the engine being forced backward. Helps minimize impact damage to the transom of the boat and the engine itself. They are not usually a maint. item. The more modern power trim/tilt systems have this same internal protection built into the trim/tilt systems.
