5 BS problem....anyone?

[pearcey]

A number of problems with this engine which is new to us.....can any one tell me the points gap please?
Also, it has a weak yellow spark & starts/runs on low revs OK but will no take any throttle.(spluttering/backfiring). Any help would be appreciated.

[boats.net]

I'm not sure what model you, don't have a 5 BS listed unless it's sold by Yamaha Motor Corp LTD which is not sold here in the USA, but none of the motors sold here use points, they all have CDI ignition.