RV Repair: onan generator starting, battery boost, battery switch

Question
I am a newbie.  If I start my motorhome then push the generator start it fires right up an works correctly.  I can turn off the motorhome and it keeps running.

I cannot get it to start unless the motorhome is running.  What am I not doing correctly ?

Thanks
Jack

Answer
Jack, First let me tell you it sounds like you are doing everything right, but that the battery that starts the generator is not charged enough to start it. That is unless it is wired to the wrong battery and it is dead. Does your motorhome have a battery switch that will connect both batteries together. Sometimes they are referred as a boost or battery boost, or even emergency start. Try pushing on this if you have one and seeing what happens then. If it starts then this was the trouble. If not then let me know and please give as many details as you can as to exactly what happens when you try. Thanks, Bill