2014 40 HP Mercury 3-Cylinder EFI - No Start

Hi all. New to forum. I have had this boat (2016 Tracker Grizzly 1860) and motor (see title) since 2016. Purchased brand new. Went to start it up this week to get ready for winter storage (with ear muffs in place and water on) and it won't crank. The starter Bendix pushes the pinion up and engages the teeth on flywheel, but doesn't crank (but tries too). Tried all the usual things:
- Checked/cleaned connections on battery, starter and solenoid
- New battery (12.71 V)
- Removed starter and solenoid and had them bench tested at a reputable "auto electric" establishment. Both checked out.
-Tried pull starting too, but I don't have enough strength to get through more than one compression stroke

Only thing I can figure is there is higher compression than usual for some reason, stopping the starter from cranking the motor.

My next step is to reinstall starter and solenoid, pull plugs and try cranking again. Maybe fuel leak into cylinder(s)?

Any suggestions?

View attachment Merc Start Video.mp4

Welcome
You bought it new and this is the first time having this kind of issue

I would suggest start with the easy stuff. Pull plugs and crank to see if any liquid comes out. If no liquid, start checking Bat cables and connections. Could be a corroded cable/connection and full Bat voltage is not making it to the starter

Thanks alldodge. My thoughts exactly. I've been through all the connections from the battery to the solenoid and starter so far (the relatively easy ones to get to). Ground points and other connections inside the motor housing will be a pain, but gotta do what I gotta do! Yes, bought it brand new and the 1st time I've had an issue like this. It's been a solid watercraft to this point.

One point that I need to pursue as well: I read somewhere that my motor has some kind of "compression release" during start up. Have no clue how it works, but maybe another avenue to investigate. If that is in fact the case, would make a whole lot of sense (my little pea brain talking).

Positive waves always!

Still getting used to attaching files. A classical reference.