SUITABLE 35c-40cc ENGINES TRIMMERS USING THICKER LINE CAN RESULT IN DAMAGING THE MOTOR. WHY IS THE TRIMMER LINE NOT FEEDING PROPERLY?THERE ARE THREE THINGS YOU CAN CHECK. 1/HOW OLD IS YOUR LINE OR HAS IT BEENEXPOSED TO PROLONG PERIODS OF HEAT OR LIGHT. 2/BE SURE THE LINE IS WOUND PROPERLY ON THE HEAD. 3/ LETTING THE LINE GET TO SHORT BEFORE PULLING MORE LINE THIS WILL CAUSE MELTING AND BREAKAGE