Small Engines (Lawn Mowers, etc.): chainsaw, correct pitch, plastic case

Question
I own a factory reconditioned McCulluch made in '99. Plastic case. Nice saw, but after it gets warmed up the chain gets so tight that the engine won't pull it. I correctly adjust the chain, again and again after about 1 minute, it won't cut again because the chain is to tight AGAIN !! The only way is to start out with the chain very very loose !!  Any ideas?  Thanks !!!

Answer
HI STEVE


DOES THIS MACHINE HAVE FRONT MOUNT BAR ADJUSTER OR  SIDE MOUNT BUILT INTO THE CHAIN COVER /

IS THE SPROCKET AND BAR IN GOOD CONDITION ?

WHAT ABOUT THE CHAIN  ?  IS IT THE CORRECT PITCH  AND GAUGE FOR THE BAR  IE 3/8 LO PRO -0.50
OR .325- 0.58

DOES THE CHAIN TENSIONER ADJUST ITSELF WHILE RUNNING UNDER VIBRATION

IS THE BAR/ CHAIN COVER CLAMPING UP THE BAR PROPERLY WHEN YOU TIGHTEN THE BAR NUTS

ALMOST SOUNDS LIKE CHAIN IS PULLING THE BAR TIGHT WHILE RUNNING
AS IF THE BAR ADJUSTER PIN IS NOT HOLDING IT IN POSITION


HAVE A LOOK AND LET ME KNOW WHAT YOU FIND

CHEERS PAUL