200 EFI - Starts once, then won't start

[Dereck123]

I have a Mercury/Mariner? 200 EFI , the serial number has been painted over and I can't find it anywhere else on the engine. I assume it's a late 1990s model.
The motor starts up fine, though a bit smokey. I can go anywhere I want on the first run of the day. But then, it does not want to start again. It turns over and sound like it wants to start, but never actually does. If I wait until the next day, it will start again but only for the first run
Recently, I've started lifting the motor after my run. Once I put it back down, it starts! As long as I lift the motor when I'm done, I can run multiple times
At wot, I'm getting to about 5100 rpm at 58 mph with a 26 tempest on a TR-20. Occasionally an alarm will go off when I'm idling for what I assume is low water pressure since it happens when the water pressure gauge goes to about 0. I can negate this by hitting the gas if I notice the gauge dropping

Any ideas on issues? Compression and spark are good, however one cylinder is a bit more black/burnt on the spark plug than the rest

[JOE54]

rectify low water psi problem at low rpm service w/p ,sounds like you have a manifold fuel leak or possible broken reed

[EuropeanAM]

Also- check for welch plugs in the engine block (about 1" diameter, with serial number stamped into it). If not, at least a couple pictures of the powerhead (if it's a late 90's engine, very unlikely you have water pressure being monitored).