Well I completed the flow test with the carby bowl removed last night and I am now confident I need a new petrol cap, unless of course you think otherwise.
So the result went like this:
1) I opened the fuel tap and the stream out of the carby bowl was steady, then after about 5-6 seconds it started to splutter, however when I took the cap off the fuel flow returned back to a steady stream.
2) When I tightened the cap back up after 5-6 seconds the fuel flow started to splutter again
So from this test I gathered the part of my petrol cap from earlier photos definitely has a purpose. I do apologise for not conducting this test properly in the first place. With the carby bowl removed the results were much more obvious.
Secondly I noticed a feature in the manual about setting the throttle linkage correctly. It specifically referred to the governor arm mount being would clockwise before installation with the throttle butterfly in the open position. I might need to repeat this process if you think worthwhile.
