I only ever use NGK or Bosch plugs and yes that was kind of part of the problem.
Another guy tested the magneto and said it was on they way out...I have to trust him on that.
The real problem was the throttle cable which had become frayed, stretched and nearly broken inside the outer protective layer.
It must have just been hanging on just enough, to cause intermittent trouble, and stretching so in the end it broke and was not engaging the choke or the throttle control at all.
I couldn't get an original cable, and had to settle for another generic one, (it's control arm works opposite to the original Masport one) which was quite a fiddly fit and I had to cut quite a lot off the cable and inner wire to fit my mower.
I remembered a tip which was to first remove the inner wire and cut the outside cable cover before fitting the inner wire back on and shortening to suit.
The z bend tool I also bought with the cable came in real handy but it took me a few goes to perfect the z bend technique.
After installing the new magneto, spark plug and throttle cable the mower still wouldn't start UNTIL I realised:
1. the new plug had no visible gap straight out of the box (never happened before and I didn't notice when I installed it) ..maybe I bumped it or something.
2. the plug connection, as part of the new B&S magneto, had a much longer boot and required pushing much deeper onto the plug cap.
After that it fired up and after a few start stops, kept firing first pull.
Maybe I could have got away with only a new throttle cable
Thanks to everyone for their input and hopefully I get a few more trouble free years out of it now, rather than posting again with more troubles
It's more a learning journey for me rather than paying a hundred dollars an hour at a mower shop
Last edited by Geesey67; 28/07/24 04:57 PM.
