582 battles after heavy load?

[Robin Hood]

For the second time since I bought my Aquilla 582, I have had absolutley no response when trying to start the engine. Situation as follows both times:

Cold winter morning.
Pax heavier than normal and have to fly at 5 800 rev + to stay in the air.
No problems starting at airfield .
Flew 20 minutues and landed.
When I then wanted to start after that, no go. Engine turns OK but not even a backfire

Check plugs, carbs. All OK.

Crank till battery starts giving in. Pull start till I nearly drop. Nothing.

The suddenly it starts again and runs like a well-oiled sewing machine.

Fly 20 min back to field and it starts at the first crank after landing.

Could I have carb icing AFTER lanfing? Could it be the extra weight doing something?

Never happens when I fly solo.

Any thoughts would be welcome!

[3wheels]

This might sound silly, but check your fuel breather(pipe on filler cap) to see that it is not blocked............. The pax sits on the tank in the Aquilla, if your breather pipe is blocked, the fuel will be forced opposite direction causing flooding. ( It is after all only when you have a heavy pax ) Just a thought !!
If my tank has 40L in and I put a 80KG + pax in the back, my breather pisses out about 1,5 to 2L........If this could not come out the breather it would build pressure to the motor.

Morph, Duck need some help here