More trim gauge issues

[Coastal Mountaineer]

Added a Faria analog trim gauge to dash. 2020 Mercury 150xs, 2B699863 engine with trim sensor converter kit. Works but trim range is shown on the first 1/4 of range printed on the gauge face. After that, the engine enters tilt mode and the gauge needle keeps moving to top of the trim range on the gauge face. As the engine keeps tilting up, engine loses bite and revs increase until rpm limiter cuts power and engine sounds bad.


How do I adjust the gauge on the engine to reflect just the trim range so that when the gauge moves to the top I'll know I'm about to raise engine too much?

Or, is this the way it's supposed to be?

[low slung cruiser]

That’s the way it’s supposed to be

[EuropeanAM]

Usable trim range (what you can use when in forward gear, and above 2500 RPM) will display as approximately 1/4 to 1/3 on the gauge face.

You should NEVER attempt to continue raising the engine high enough to bring the prop out of the water while the engine is running (in OR out of gear). Doing so potentially robs the engine of proper cooling, AND CAN CAUSE CATASTROPHIC ENGINE DAMAGE.

The PCM records such severe events in it's history, and in the event of a major failure, Mercury requires a copy of that history.

[Coastal Mountaineer]

Usable trim range (what you can use when in forward gear, and above 2500 RPM) will display as approximately 1/4 to 1/3 on the gauge face.

You should NEVER attempt to continue raising the engine high enough to bring the prop out of the water while the engine is running (in OR out of gear). Doing so potentially robs the engine of proper cooling, AND CAN CAUSE CATASTROPHIC ENGINE DAMAGE.

The PCM records such severe events in it's history, and in the event of a major failure, Mercury requires a copy of that history.

Thanks guys, this is the info I needed. I ran the boat yesterday, watching rpm's and yes, staying within the first 1/4 of the gauge kept me in the correct operating range.

Don, previously I pushed too far on the rpm's/trim maybe 5 brief times. Each time the engine hit approximately 6300 rpm as measured by my Faria gauge and just under 6,000 by Vessel View Mobile, it immediately dropped rpm's down to 4,000 or so. I cut throttle almost immediately afterward, but in reality that probably took me 1 or so seconds to do. I did not get any warning lights or horns going off during or after these brief times. When I ran it correctly yesterday, I didn't notice any problems.

Given the possibility I may have damaged engine, should I take it in now for a Mercury mechanic to check for damage and repair? Or just wait it out and hope for the best? If I wait, is there anything I can do myself now that might help prevent future damage?

[EuropeanAM]

If water pressure is ok, and engine is cooling properly, you are probably fine. Recommend the next time you are in for maintenance that you mention this to them so that they can check the Freeze Frame History for related faults (most overspeed faults have been removed from warning horn/fault status, though Guardian will take over and do it's best to prevent engine damage).

[MichaelJ3]

Seems to me the useable trim range is set too high if you can consistently trim up to the point where the prop blows out and RPM's are limited? What am I missing, Don? Shouldn't that be adjusted too, or is it not adjustable?

[EuropeanAM]

There are two functions involved- both the reported trim position (PCM monitored), and the hydraulic limit or bypass inside the trim system.

And if the throttle isn't advanced past approximately 2000 RPM's, you can probably trim the prop right up out of the water (of course this is NOT a good idea).