ONE OF THE OLD TRICKS WITH MY INVERTED OS 77 DUCTED FAN ENGINES WAS A OS #8 PLUG AND USE A SMALL PICK OR STIFF WIRE AND BEND THE TOP COIL JUST A SMALL AMOUNT UP SO THAT THE COIL WIRE IS STICKING UP PAST THE BODY OF THE GLOW PLUG. THIS KEEPS THE COIL GLOWING BETTER WITH THE COLD AIR FUEL CHARGE COMING INTO THE ENGINE. REMEMBER THAT WHEN THE METHANOL AND AIR MIX AT THE CARB IT GETS REALLY COLD TO THE POINT OF ICE FORMING ON OUTSIDE OF THE CARB. SO RUNNING IN COLD WEATHER AMPLIFIES THE PROBLEM. ANOTHER LITTLE TRICK MY CHEMIST BUDDY CAME UP WITH WAS 1/2 OZ. OF AC PUMP OIL TO ONE GALLON NITRO FUEL,,,, WHEN THE AC OIL BURNS IT PRODUCES OXYGEN AND WE ALL KNOW THAT FIRE IS NOT FIRE WITHOUT OXY. WE USED TO RUN THE JETS IN COLD WEATHER AND GETTING THEM STARTED WAS HARD. POPING GLOW PLUGS SOUNDS LIKE LOTS OF FUEL WITH NO GLOW IF THE COIL IS NOT BURNED AND CRUNCHED UP INTO BODY OF GLOW PLUG, OR IF THE COIL IS BURNED OFF THEN SHES GLOWIN BUT TO LEAN ON THE FUEL.

ONE OF THE OLD TRICKS WITH MY INVERTED OS 77 DUCTED FAN ENGINES WAS A OS #8 PLUG AND USE A SMALL PICK OR STIFF WIRE AND BEND THE TOP COIL JUST A SMALL AMOUNT UP SO THAT THE COIL WIRE IS STICKING UP PAST THE BODY OF THE GLOW PLUG. THIS KEEPS THE COIL GLOWING BETTER WITH THE COLD AIR FUEL CHARGE COMING INTO THE ENGINE. REMEMBER THAT WHEN THE METHANOL AND AIR MIX AT THE CARB IT GETS REALLY COLD TO THE POINT OF ICE FORMING ON OUTSIDE OF THE CARB. SO RUNNING IN COLD WEATHER AMPLIFIES THE PROBLEM. ANOTHER LITTLE TRICK MY CHEMIST BUDDY CAME UP WITH WAS 1/2 OZ. OF AC PUMP OIL TO ONE GALLON NITRO FUEL,,,, WHEN THE AC OIL BURNS IT PRODUCES OXYGEN AND WE ALL KNOW THAT FIRE IS NOT FIRE WITHOUT OXY. WE USED TO RUN THE JETS IN COLD WEATHER AND GETTING THEM STARTED WAS HARD. POPING GLOW PLUGS SOUNDS LIKE LOTS OF FUEL WITH NO GLOW IF THE COIL IS NOT BURNED AND CRUNCHED UP INTO BODY OF GLOW PLUG, OR IF THE COIL IS BURNED OFF THEN SHES GLOWIN BUT TO LEAN ON THE FUEL.

SORRY I POSTED TWICE AND CANT SEEM TO DELETE ONE.

f16man, this trick also works on engines in warmer weather as it exposes the coil more to the fuel/air charge.
I deleted your duplicate postings. I have that problem once in a while also.

try starting it with a hot range plug. fine element, and with an idle bar. This might not last with full bore running but you can use it as a start-up plug to warm the engine, then take it out and switch to a med or cold plug...depending on your nitro percent.

im running 15%nitro an 18% oil and i got my motor to start up here at the house i used a drop of lighter fluid and first crank it came to life and it started everyother time past that so if it gets to the point it wont start im just gonna drop a lil drop of lighter fluid in it and hopefully with a combination of warmer tempertatures and fresh nitro i say it should run fine or just fresh gas it self!!!