well that was the advice i was given
Someone has given you some wrong advice!
If you have to pour fuel into the plughole to start a motor, any motor, there must be a serious underlaying problem.
If a motor has good compression and has a leak free and clean working fuel system, it should start by using the choke.
If there is an air leak, blocked or wrong size jets, or incorrect float level, then the motor could be coaxed into starting by chucking fuel into the plug hole.
Each time fuel is poured into the plug hole, the life of the motor becomes shorter as the fuel dilutes the ring lubrication causing them to run dry in the bore.
Pre mix has absolutly no lubricating qualities unless it goes in through the crancase.
Do yourself a favour and do some diagnostics on your starting problem before it costs you heaps of money, if it hasn't done so already.
Check the compression, do a leak down test, and give the carby a good cleaning. If nothing else it will save you a s**t load of time taking that plug in and out,
I would hate to think what the threads are like in the head.