replace in line fuel filter but cannot see fuel going into carb.do l need to prime pump or it there another filter that l am missing.also the carb butterfly(do not know the right term) remains open .the other engine remains open all the time .could that be the reason?

The butterfly is the choke. These often stick or fail alltogeter.
They have noting to do with the fuel issue. When air is interduced in the fuel line it will take time for it to make it way thru the carberator.
If the engine does not start try staring fluid.

First ,the ''Butterfly'' is the Throttle Control,and should be normally closed,only opening by the control lever.check that Vent is open.&Fuel
Cock open,fuel should now fill the Carb.


Second,Try not to run your engine dry,it can pick up dirt/sludge etc.