EMB ERJ 135 ER/LR
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff
Human Factors
Although the Gust Lock had been released; it was not fully forward and unlocked.  I noticed the First Officer checking the flight controls; while I was confirming the final was clear and setting the lights for takeoff.  As I began pushing the thrust levers forward to set thrust; I noticed the Gust Lock had not been fully released.  We decided to abort the takeoff; taxi back; release the Gust Lock to the fully forward - UNLOCKED -  position and 'try again.'  The speed was no higher than 25 KIAS as minimum effort was used to brake to a stop and the spoilers never deployed.  The First Officer did not release the Gust Lock and I did not confirm it was fully forward.
EMB135 Captain reports rejecting a takeoff at low speed when the thrust levers are blocked by an incompletely stowed gust lock.