To be 100% clear... here's the exact scenario... Run the engine at 3500-4000 RPM cruise to lunch, approximately 30-45 minutes. Oil temp around 160, water temp around 150, 63 degrees outside temperature, water pressure at 25-30 psi (ie: very normal operating conditions). Have lunch, sit for an hour or two, engine hatches raised on shut down. Finish lunch, go to restart, turn key, engine cranks normally but will not start.

As I turn the key on the second go, I push the throttle forward to approximately 2000 RPM position and you can hear a cylinder or two fire as its cranking (you can hear the exhaust blast) but it will NOT start just by advancing throttle. I need to pull the throttle back to idle position and push forward again and keep rocking the throttle (ie: pumping the throttle back and forth) between idle position and 2000 RPM position while I'm turning the key and with each iteration of this, you can hear a few cylinders firing (like she's trying to start) and then eventually she fires up. The best way I can think to describe this is like a pull cord lawn mower. Pull the cord the first time, nothing happens.. pull the cord a few more times and you start to get a few coughs... keep pulling the cord and eventually, the engine starts..

Once it's lit, it stays running and runs completely normally. If I were to shut it down immediately and restart it, it will fire right back up. It's only on the first try after its been sitting.

It's the accelerator pump, ur a carb guy lol......... when you first turn the key to the on position can you hear the high pressure pump pitch change from high to a lower tone, this happens when its putting pressure to the fuel rail or does it stay at a higher pitch meaning there's no fuel to push

I had the same problem last year with one my 525s. It wasn't setting any codes so started swapping sensors between engines one at a time. It ended up being a coil pack. To this day I don't understand how giving it throttle would help a bad coil pack! Might be with a shot to swap them.

Were you having the exact same symptoms as I described above? How did you determine it was the coil pack??

I'd take your laptop out on the boat with you, hook it up while you are at lunch, and prior to cranking - key on, what does ECT say? I'm with BUP, my guess is this is engine control related - and the first place I would go if I was diagnosing.

Yep, that's the plan.

How many times does it take turning the ignition key over ' crank engine over to get it to start - it looks 3 times -

The scenario is - 1. we have no start turning key over - throttle at idle setting, 2. then we have advance throttle turn key over again no start -3. then we have pumping the throttle and turn key over again the engine will start this time - Correct Anything on your part to add to this ???

Take advancing and pumping the throttle out of the mix - leave it at idle setting, turn the key only to on position - NOT starting mode / cranking mode - do you hear your fuel coming on ? if so do this same procedure 4 to 5 more times - key on - fuel pump running - when fuel pump stops turn key off - do this 4 or 5 more times - this is cycling the fuel pump - after that does the motor start
( leave throttle in idle setting and do not move it ).

This might take 2 people one at the key switch and the other to listen for the fuel pump running ? Sorry trying to narrow this down - it is always good to give out as much detailed info as you can plus the depth of it - trying to find out these problems.

I have more to post about your throttle plate setting and the IAC value - I will post it very soon.

You have sequence correct

Roger I am crystal with the sequence. Just staying with it and tying to follow along

And you're doing a great job at that... thank you for your help...