An INTERMATIC Repeat CYCLE timer is whats used on the Keystokers for the IDLE, it a 0-30 MIns Repeat cycle time, you can put PINS in for 15 sec intervals.
somethign like thishttp://www.smarthome.com/25117/Intermat ... tes/p.aspx
My Keystoker for idle runs 6 pins every 10 mins to keep the fire, but you could set it with more pins for a bigger fire to maintain heat...
Also, If you can find a SPEED control/Rheostat for like a power tool (Like a router, etc..) you could use that to slow down the FEEDER Motor. It should be able to handle at least 1 amp, I dont think the stoker motor draws much power. MIght work temporary.
This link is broken, either the page no longer exists or there is some other issue like a typo.