Amanco Hired Man, running problem

l bought a hired man last year and have run it several times, it is a hit and miss engine running off a mag with a straight striker arm, when starting I turn the control from 0 (closed) to 5 (one turn) it then starts easily with a couple of spins of the flywheels, when started I turn it down to a point between 4 and 3, if I do not do this the engine stops after a couple of minutes and I need to remove the ignitor and clean it of heavy soot deposits, NOW, my problem is that when stared and running the engine fires and it gives quite a loud "crack" and it exhales quite a lot of smoke, when I turn it down it does produce slightly less smoke but still a noisy firing, if I turn the control to under 3 even a small amount the engine starts to miss, I heard the engine running prior to my purchase and it was quiet and no noticeable smoke from the exhaust,
the only thing I have done is to replace a couple of damaced springs on the striker and detent arm, it is possible that the square striker arm may have turned in either direction while doing this as it was not locked in position when I replaced the spring, but I do not want to start doing any adjustments until I hear some comments or advice from others who know better than I do,
Any or all advice or opinions will be gratefully accepted Rupert.

Would it help to get some/any replies if I were to attempt to explain the problems diffeerently?

Can't help personally I'm afraid, but I would expect someone to pitch in.
Maybe post some pictures or better still a video?

Have you checked the non-return valve in the fuel line? Is the brass ball seating correctly?
Eric

hopefully this link show show the problem the microphone on my phone is not the best and the actual "crack/bang" when it fires it quite a bit louder than you will hear
[url=20220917_131447[1]]20220917_131447[1][/url]

sorry chaps, there seems to be no facility to show a video taken with my mobile phone, it is downloaded to my pc but this site facilities will only accept a link with URL which for obvious reasons does not exist only a pc genereated photo/video number

If you have an account then post on youtube then use the youtube button in Edit to insert link.
Otherwise use another video streaming service e.g. Streamable, Dailymotion etc and copy paste full url here.
Good luck.

If you are having trouble with video, let us know and someone, me included, could post it for you.

Also, have a look at this thread.

https://ukengineforum.forumotion.com/t7145-amanco-hired-man-starting-issues