Clint Jensen and Dan Swanson shared third place at 8-under-par 132.
Wisler has adjusted well to the rain-shortened event on the Crenshaw Cliffside Course at Barton Creek Resort.
After the tournament was reduced to 54 holes following Thursday's washout, the American has put together two solid rounds in search of his second career victory on the Canadian Tour.
Kanada, who is looking for win No. 1, posted a 66 of his own to finish alone in second place at 9-under-par 131.
Andy Johnson and Kris Mikkelsen tied for fifth place at 7-under-par 133.
Rob Oppenheim, Peter Wilson, Danny Mijovic and Danny Paniccia were one shot further back at 6-under-par 134.
Alex Rocha, Paul Devenport, Marcus Jones, Darren Griff, Rafael Gemoets, Lee Curry, Jason Allred, Casey Bourque, Adam Speirs, Craig Taylor and Zoltan Veress shared 11th place at 5-under-par 135.
The 36-hole cut fell at even-par 140. Last year's winner Rob Johnson failed to qualify for the final round after finishing at 1-over-par 141.