2001 Merc. 200hp Opti – Starting/running problems?

Finally got trim/tilt fixed - trim motor shorted taking out the wiring harness & trim relays too. Replaced all at Mercury marine dealer, works great now. Though put in water first time since Aug. of 2019 ( health problems), motor started immediately, ran about 15 min. while getting ready in boat, idled 100 yrds. numerous rigs in area then started to get on plane - half way then motor stalled, shut off. Next couple hrs. tried to restart a number of times, waiting in case flooded each time, would start then stop instantly or would turn over but not start? Gas has been in this rig approx. 15 mo., have put stabilizer in several times since then, including a few days before putting in water. Trying to get rig ready to fish, hoping to be able to fish next year? Any ideas that might help? Likely will take into mechanic again but they are booked well into Jan. 2021 now. Note - just checked and primer bulb is not getting hard at all, assume motor not getting fuel.