What do I need?

[Blackwoodz]

New to boat/engine setups with trim. Up till my current setup I just had manual trim setups. .place rod in motor mount at trim.
My current setup is an old Swift with a 99 efi 150. I have put a trim guage in the console and it all works. I hear guys talking trimmed all the way up while dialing in the setups. I currently just watch my guage and it's usually a few lines from being down and stop when it starts throwing water above cowl. What do I need to make this fool proof? So it quits trimming up without me looking at guage or for roost?
I'm trimming it from my control lever button.
Thanks for guidance.

[jarhead175]

Motor stops at the top of trim when above a certain rpms as a safety to keep you from lifting it out of the water. Full throttle and trim up till the motor stops itself then look at the gauge that will be top of trim.

[Blackwoodz]

This switch is built into the engine wiring? I'll have to check it's working.

[mdtritn21]

The hydraulic rams on the trim have a relief valve that normally keep you from over trimming when running at speed.

[Rip Bass]

What they mean is,you have a two stage trim assembly. The two short rods trim up while under power and the one longer rod in the center is for tilt,raising the engine higher for trailering. You don’t necessarily have to have full trim for best performance. Lots of boats run better at less than full trim and will slow down at full trim. You’ll have to experiment with yours to see where it runs better as every boat is different.

[Blackwoodz]

Yeah figured out Friday on Holloway res....I guess I thought engine would raise out of water at higher rpm. I did find I can only trim about 1/3 on guage before I hear tone change and it starts tossing water above cowl. Thanks guys.

[mdtritn21]

1/3 is all most Merc's show on the gauge at full trim so that's normal with the rest of the movement being tilt. You may not have to run it full trim but that's up to the boat and the load.