1st post here so thanks to all in advance. 1st trip on newly acquired 1998 Mako 20/1998 Johnson 150. Initial start to motor required full advance of throttle in neutral and application of key choke. Motor warmed up fine: no excessive smoke, good water coolant pressure, no motor alarms. Motor ran perfectly through idle, power up, & cruise rpms to destination (approx 35 minutes). Motor started perfectly after lunch and again after fueling (filled tank from 1/4 to full) with throttle in neutral detent position (no advance of throttle needed). Motor ran perfectly back to home dock and tie-up. 2 hours later motor turns over fine but, will not start. Fuel and oil primer bulbs checked with appropriate pressure to each. Attempted to start motor with throttle in neutral detent positon and with throttle in advanced neutral position without result. Not even a hint of fire. Reset install of cut off lanyard without result. Since I am brand new to this motor and the failure was so abrupt, I was wondering whether I was missing a simple and obvious solution. Many thanks. Tom