Genie s-40 starts then stalls

I have a 1999 Genie s-40 425lrg [2.5 ] EFI motor, The last user put diesel fuel in the gas tank, about a 50/50 mix . I drained the gas tank and installed a new fuel filter and after a dozen tries it started. It smoked a little and I ran it at high speed and at idle for 5-6 minutes and then I shut it off. I replaced a leaking valve cover gasket and installed a new set of plugs while I had it apart, also oil and filter change and changed out the hyd. filter element.I tried to start it after that work and it would start up and run 2-3 seconds then shut right off . I replaced the MAF sensor and it would not even fire , put old sensor back on it and it would run 2-3 sec. and shut back off. I checked the relays , they are o.k.

I am not getting any codes from the machine. Any ideas ?

Genie s-40 starts then stalls