volvo aq125b stalls when put in gear ?

[surge006]

I have a 1986 volvo aq125a with a 270d outdrive. The boat has been running great all year. I took it out last sunday and it took a lil longer to start and i was suprised cause i was out sunday before and also on wed. so boat wasnt sitting. I put fresh fuel in before i left on sun. When the boat did start it ran fine. We stopped a couple times and restartde threw the day, then one more time and nothing, kept cranking and cranking and would want to start when i would stop with the key but nothing. Finally after bout a couple hrs it would start and idle fine and rev fine in neutral as soon as i would put it in gear it would die. It did this bout 50 times then finally stayed in gear with no throttle to get me to ramp. Then randomly ran fine at wot then back to stalling.
Now i did my beging of the year tune up on it. plugs, cap, rotor, points, condensor, fuel filter, coolant, thermostat, oil & filter. do you think im looking at a electric problem or fuel ? Any help would be great not sure where to start thanks John