Just a heads up that may interest users of the Mariner/Mercury 15 2-stroke motors.
With my 2001 Mariner 15 owned up until earlier this year if you put it in neutral between short bursts in gear nosing into a beach and came over a high spot the motor would lift over the obstruction as you drifted over it in neutral which is how I expected it to be.
When lubricating and testing the tilt/reverse lock on this identical 2004 Mercury 15 I've just bought with my Zodiac outfit I could see it would only tilt in forward gear... locking down in reverse (of course) and neutral.
Had a look in the workshop manual Max linked to in another thread and here is the page that deals with it...
Boatinfo - Mercury Service Manual for 6-8-9,9-10-15 hp
... and it gives the setup instructions for operation with tilt lock in just reverse or reverse & neutral.
I've changed mine to my preference of tilting in neutral as well as forward.