If the idle adjustment does not work......
I am thinking that both of you may have a air leak. You have enough fuel in the IP and lines to start, but then a air bubble comes through and kills everything. You hit the starter which pushes the bubble through and off you go. Just for grins if you have a hill and can park it overnight on it, try it, nose down one night, nose up the other. Any difference? Another test is when it quits, don't use the starter, but use the primer button on the LP. Do you feel that it is pumping air or fuel?
I am thinking that both of you may have a air leak. You have enough fuel in the IP and lines to start, but then a air bubble comes through and kills everything. You hit the starter which pushes the bubble through and off you go. Just for grins if you have a hill and can park it overnight on it, try it, nose down one night, nose up the other. Any difference? Another test is when it quits, don't use the starter, but use the primer button on the LP. Do you feel that it is pumping air or fuel?