Wilbur wrote:
My MH 5k gen is dead! Thinking about replacing it with a 2.8K to power roof air while on highway and maybe a coffee pot too. The MH has 2 circuits; a 30 amp and 20 amp. The power cord plugs into an on-board receptacle for genrator use. Since the 5K had L1 and L2 circuits, it seems that they can be wired together to connect to the new gen output wire. That should make both cicuits hot with a total limit of 30 amps.  Is this correct?
Short answer: YES.
Longer answer... I am assuming your RV is a 50 amp... IF you plug in using a dogbone adapter at a 30 amp site.. This is EXACTLY what happens in the adapter
True 50 amp outlet
50 amp service
   Neutral
L1  (Hot)  l2
   Ground
50 amp to 30 amp
Adapted outlet
   neutral
Hot ------Hot 
    Ground
The two hots are connected together.
So the 30 amp dogbone does exactly what you are planing, IT WILL WORK