Trim Issues with 2017 Mercury Pro XS Fourstroke

[RangerKing]

<2B397940>

Trim Issues with 2017 Mercury Pro XS Fourstroke
Hello, got a question for you guys and seems like you all got more knowledge than most dealers, so maybe you can help me out. I have a Mercury 115 hp ProXs fourstroke that I have had for over 4 years, I am the only owner of this boat. I have always been able to trim the motor up and squeak out about 46 mph on the Ranger RT 188 at least to the point the boat starts porpoising and have to trim down slightly. But recently can't get over 40mph and motor will not trim up as much as it always has at WOT. When boat is idling or sitting on the trailer motor will tilt fully up out of water with no issue. Any idea what the cause of this issue is. i.e. trim limit switch or trim position sensor. Help please.

[EuropeanAM]

Check the engine and jack plate hardware
and fasteners first.

If you would, please take a moment to review the Announcements at the top
of the forum, and be sure to provide the Required Info (serial number) when posting. Thanks!

[RangerKing]

Thanks for the reply Don, my motor serial number is 2B397940.
Also I checked the mounting hardware and cannot find anything loose. Checked fluid level and it is topped off to level with fill hole. While checking it today sitting on trailer in garage noticed that when motor is a about 3/4 trimmed up there is a creaking sound. Can't pinpoint exactly where it is coming from. Also makes the same creaking sound toward the bottom of the circuit. Definitely not a sound that I have heard before. Got a video of the sound but not sure how to post it here.

[RangerKing]

Watch "October 19, 2021" on YouTube

[RangerKing]

Watch "2017 Mercury ProXs Trim Issues at WOT" on YouTube

[EuropeanAM]

Check to see if you have a A2D Converter and Trim Limit Module on the front of the engine.

Unclear from the second video exactly what you were doing or trying to do... it almost sounded like the warning horn was sounding (likely due to an overtrim condition based on trim sender's signal at that point). Engine RPM's are limited if trim is above the maximum TRIM angle.

First Video- make sure the tilt/steering tube has been lubricated (should be a grease zerk facing forward, right in the middle of the swivel bracket "boss").

[RangerKing]

Thanks Don, checked and lubricated the tilt steering tube, no issues there. Also I assume you are referring to A2D converter as analog to digital converter. Not sure where this would be located, under cowling or on front of trim assembly. What I was trying to demonstrate in the video was that the motor at WOT will not trim up into the same range that it always has, the sound you hear is me continually tapping the trim switch. Thought it might be useful when it took it into my dealer. Not being able to trim up as much is stopping me from getting the same speed and performance as I always have. Have lost about 6 mph since it started acting up. Is there an adjustment for the trim angle.

[EuropeanAM]

The 115 does not have an adjustment (electronic).

Just to clarify- you were repeatedly ACTIVATING the trim. Were you also repeatedly stopping it (or was it stopping itself before you released the switch)?

[RangerKing]

The 115 does not have an adjustment (electronic).

Just to clarify- you were repeatedly ACTIVATING the trim. Were you also repeatedly stopping it (or was it stopping itself before you released the switch)?

Answer to your question. I was repeatedly activating the trim, but it will not trim up any higher. Just stops and will not trim any higher.

[EuropeanAM]

Still not clear. Let's temporarily forget about the motor moving up and down and talk ONLY about the sound the trim motor makes when you push the switch.

"When you were in that video, and pushed the switch UP, did the sound of the trim motor continue as long as you had the switch depressed, OR did it stop before you released the trim switch"?

This is a VERY important question....

[RangerKing]

Yes, as long as the button is depressed the trim motor continues to run just will not trim any higher.

[EuropeanAM]

Check for excessive tilt or trim leakdown (with boat on the trailer), if all above mentioned hardware are in appropriate condition.

[TritonTRXV8]

That creaking sound is the pivot pin at the top of the trim ram. Spray it with a teflon lubricant and i bet it goes away. My old 115 opti did the same think. I just sprayed that pin every time i serviced it and it never did it again.

[clayshooter100]

Make sure the manual relief valve is tight if you haven't checked it yet.

[RangerKing]

TritonTRXV8 you are correct. I did spray some Teflon lubricate and it did stop the creaking noise. Took the boat to the lake today just to get better idea of what might be going on. So I put the boat in forward gear and checked the RPMs on Vessel View and at about 800 RPM I am able to trim the motor up as normal but as soon I increase the RPM to about 1500 it will push the motor right back down. Leading me to believe that either the cylinder seals are bad or the Up circuit pressure relief valve is defective. Don I will definitely check and see if the motor trim leaks down over night, something that I haven't checked because of limited space in garage and have always stored the boat with motor down. Will include a video to show how the motor just will not hold its current trim position. Thanks Guys

[RangerKing]

Watch "Motor Trim Issues" on YouTube

[Savage]

I believe you are trimming the motor too high for the RPM and amount of throttle you are using.

[RangerKing]

Thanks for the help guys, took it into my dealer today and they are going to just replace the whole trim assembly under warranty. So I appreciate Mercury for standing behind their product, not enough of that these days.

[EuropeanAM]

Good deal. The way it was reacting in the last video is normal (as you increase RPM's, the relief system will return the trim to a safe level). Normally right around 2000 RPM range (approximately).

Glad they're getting you taken care of- it's the reason I wear black shirts.

[Savage]

Mercury is likely replacing a perfectly good unit. The replacement tilt/trim unit is going to operate the same as the video.