New style "threaded trim pin" failure

[JAZII]

SN# 3B040668

Well, 2/3s the way through a 180 mile round trip tournament the "pin" came out.
With no accurate trim referance to the PCM this IS and CAN be a DANGEROUS sititation. My motor went from 6000 rpm down to around 2000 rpm and violently back up to 6000 rpm in the blink of an eye almost causing a bow hook then having the wheel almost jerked out of my hands before I even realised what was going on.

I have been keeping an eye on the "pin", having it been loose a few times by 1/4 to 1/2 turn. I did take it out and applied red locktite to the threads prior to this trip.

Ill be taking it in for sevice for this to have it all checked out with freeze frame run reports.

I"ll post back any info that I can.

JAZII

[Jasonrs]

Is this the pin that holds the trim cylinder to the outboard bracket?

[JAZII]

This new pin is threaded and replaces the old style "tri lobe pin". It goes through the top trim cylinder clevis into a cross shaft that the trim sensor mounts to on the Port side of the motor.(same side a motor trim switch).

Is this the pin that holds the trim cylinder to the outboard bracket?

[fishnfireman]

Glad your OK!!! Bow hooks can be dangerous.
My V-8 is an early model and has the Tri-lobe pin. After reading the other post on this I've been checking it just to be sure.
Hope they get a fix for it before someone gets hurt.
After reading early reports of so much motor movement due to the softer motor mounts. Makes you wonder if that's part of the problem.
Haven't heard of any racing motors with that issue yet.

[Limbhanger51]

Can someone post a pic of the pin so I know what I’m looking at?

[JAZII]

I tried but Don's parts look up is blocked on my computer and phone for "not secure site"

[thommo59]

Once I heard about this happening to other engines, I took cable tie and wrapped it over the bolt head around the top of the trim ram. It can’t back out now

[fishnfireman]

Can someone post a pic of the pin so I know what I’m looking at?

Post # 16
trim sensor new 250 V8 (bbcboards.net)

[Jasonrs]

I just checked mine, its the bolt head style, and looks to be a bit backed out! Im assuming this should be tight? Thanks for the heads up OP!!

[smallykiller]

I'm starting to wonder if the clamping force of the bolt is not sufficient because the bolt clamps onto a rounded surface. May need to drill bolt head and safety wire bolt until mercury responds. I know of one engine that already lost bolt with under 100 hrs of operation.

[mikesxpress]

Joseph the pin backed out or totally fell out? You applied Lock-Tite and torqued it to what?

I have the trilobe pin in my V8 mfg Feb 2018.

[BorderBass]

Add me to the list of this happening. The bolt completely fell out of my 2021 ProXS 250 a couple of months ago. The same thing happened as OP to me at speed and I thought the motor got ripped off of the back of the boat. My motor had approximately 44 hours on it. This does create a dangerous situation that Mercury should be doing something about. My boat almost bow hooked too. Bolts that fall out this easily should not be a concern on brand new motors.

[Jasonrs]

I tried to snug mine up and its already quite tight, but looks like the head doesnt contact the surface its threaded into?

[rlee1fish]

Does anyone one have these in stock? Mine fell out and needing a replacement. Thanks

[mikesxpress]

Has anyone taken pictures of the "bolt" itself when removed? Curious as to the configuration size of threads.
What is the head size?

Joseph based on your history with it and applications of Lock-Tite, why do you think it's backing out?

[JAZII]

Only 6-8 fine threads into the outer one side of the end of the tilt rod.

Do a parts look up of my motor SN 3B040668 you will see why

The tri-lobe pin, hence the name has 3 different steps on the pin, 1st friction fit to outside of tilt cylinder rod, 2nd friction fit to cross shaft, then 3rd friction fit is the other side of the tilt rod end.

Has anyone taken pictures of the "bolt" itself when removed? Curious as to the configuration size of threads.
What is the head size?

Joseph based on your history with it and applications of Lock-Tite, why do you think it's backing out?

[JAZII]

Way to much force in multiple direction on two independent pieces with maybe 6-8 fine threads.

I have never heard of a tri-lobe pin failure that had not been worked on. I'm sure it's one of those one time use type of deals.

I do know when this new style threaded pin falls out and there is no trim feed back to the PCM YOU CAN TRIM IT TO THE MOON, ACTULLY TRIM/TILT THE PROP RIGHT OUT OF THE WATER AT 6000 RPM!

I now know what my Sterling needs to run properly with this 250 Pro XS 4s! Trim extenders or a set of positive trim wedges!

Has anyone taken pictures of the "bolt" itself when removed? Curious as to the configuration size of threads.
What is the head size?

Joseph based on your history with it and applications of Lock-Tite, why do you think it's backing out?

[JAZII]

Yellow circle is new style threaded pin. The dimensions given are for the thread size, pitch, and length of thread. The pin is actually longer with a smooth smaller diameter. It inserts into yellow circled rod end. High failure rate!

The blue circled pin it the old style trilobe friction fit pin. It friction fits through rod end and cross shaft. No failures.
134F8118-3FBD-4CFB-ADDE-8BD4CB454FBF.jpeg

[Jasonrs]

In the diagram, the new threaded hex head pin appears to have just a tit or unthreaded end on it, not threaded all the way??

[JAZII]

That is correct. .5" of thread then about .75" of smaller smooth pin that just sticks in cross shaft. Only .5" of thread that is load bearing.

In the diagram, the new threaded hex head pin appears to have just a tit or unthreaded end on it, not threaded all the way??