[Accelo]

Excellent outline of the cam requirements by MJN.
My only other recommendations would be sure to control the motor heat.
Motors tend to get plenty warm during a start up with out air flow and water flow.

In my experience overheating is the most common reason the motor can not be ran for the required 20 min.

1) Be absolutely sure the motor is completely full of water. Be sure to pull the upper hose and fill the block till water come out. This keeps the air pocket out of the motor.
2) Have a auxiliary fan handy.
3) Run the interior heater.