New style "threaded trim pin" failure

[JAZII]

Thanks Don.

Yes, also had that issue of no up trim.

The on the water falling out deal at speed is what scares me the most.

Do you know of any trim/tilt changes to the bleed down to trim rods? I know for sure mine will not bleed down when power loading. Set tilt to 15 and push the truck up the ramp, no bleed down to trim rods.

Yeah no go for trim extenders for safety reasons with the transom bracket design.

First and foremost- what you described is only ONE possible scenario. It's also possible that the trim may read HIGH, and prevent the engine from accelerating since the PCM would view that as an "over-trim" condition.

The best rule of thumb is to not attempt operating if or when you become aware that there is a problem in this area. Obviously- with you stuck on the water, you will do what you need to in order to get back to port.


Wedges and trim extenders are not approved for use with your engine. See engine installation instructions, and warranty/exclusions section of owner's manual for details.

[EuropeanAM]

There have been some subtle changes in the relief pressure mechanisms as it is a different system. That said- you would have to be in the TILT range (higher than the length of the short rams). The primary strategies are based on the PCM's programmed logic (and sensor inputs to the PCM), as those are the ones that can limit the engine's available power.

[JAZII]

Thanks Don!

That is what I have guessed, changes in relief pressures for this "new" style trim/tilt system.
It is proven by my own experiances on the water with failed threaded pin and feed back to the PCM. I understand what Mercury has tried to do, but it is not FAIL SAFE!
I have also proven my trim/tilt to be different than any other Mercury trim/tilt system functions.

My threaded pin has been replaced, trim/tilt reset by G3, SC Tach and dash guage recalibrated and all that functions properly.

While ON PAD UNDER NORMAL FULL THROTTLE RUNNING the system WILL NOT go above the trim rod range into the tilt.(proper function) However, while power loading, set the tilt to 15 on SC Tach and NO BLEED DOWN to trim rods or NO RPM limit up to 4000 rpm.

Thanks for your dedication to these forums!

There have been some subtle changes in the relief pressure mechanisms as it is a different system. That said- you would have to be in the TILT range (higher than the length of the short rams). The primary strategies are based on the PCM's programmed logic (and sensor inputs to the PCM), as those are the ones that can limit the engine's available power.

[mikesxpress]

Joseph with the "replacement" of your threaded bolt and recalibration did anything change in regards to the installation of the bolt? You had experienced it backing out multiple times even with Lock-Tite. What was the torque used by the shop that replaced it.

What would lead you to believe that it won't back out again?

[mikesxpress]

Like I said, no time for no money making customers.
I do not have a local friendly dealer availible to me, no un authorized people in shop area. No idea what goes on behind closed doors.

NO FAITH THAT A FAILURE WILL NOT HAPPEN AGAIN!
I will be safety wiring my new bolt. Bought a spare that will be installed without modification should I need to take engine in for warranty work.

Going to ride it out until Mercury decides to change something or a lawsuit with severe injury, or worse yet a fatality.

Picture of the new spare bolt against a tape measure and part # please.

[JAZII]

Picture of the new spare bolt against a tape measure and part # please.

I do not have a spare, on order.

8M0177279

23 in pic

[Redngoo]

I am no engineer by know means. I like the bolt ideal as far as mercury goes. But i deal with sevice bulletins alot at my job being a machinist. A bolt tighenend on a rounded surfaces never works when there is vibration. All it takes for it to turn a smidge and its loose. The correct method in my opinion would be to spot face the cylinder rod eye and use a lock washer with 100 percent surface contact

[JAZII]

I am no engineer by know means. I like the bolt ideal as far as mercury goes. But i deal with sevice bulletins alot at my job being a machinist. A bolt tighenend on a rounded surfaces never works when there is vibration. All it takes for it to turn a smidge and its loose. The correct method in my opinion would be to spot face the cylinder rod eye and use a lock washer with 100 percent surface contact

the cross shaft is dimpled as the threaded pin has a small “point” on it.

there was no reason to get away from the tried and true trilobe pin other than cost cutting.

[Redngoo]

the cross shaft is dimpled as the threaded pin has a small “point” on it.

there was no reason to get away from the tried and true trilobe pin other than cost cutting.

Ive seen this style with larger fastners and it is iffy at best. Vibration coupled with any wear on the shaft, rod eye bore and fastner will cause loss of retention. IMO with this style of retention its all about surface area contact. They do make some great retaining compounds coupled with the required primer that actually will help but not a permanent fix. Like stated I am no engineer just some knowledge in repairs of failures and using failure analysis to find root cause.

[rudapa]

Is this wonderful design still being deployed on the newest releases? I pick my new 921 Elite up tomorrow. I guess I'll find out in 25 hours.

[JAZII]

my engine born on date is 2/05/21. I was told it was a running design change, so my guess threaded pin design from here on out until Mercury decides to change something.

Is this wonderful design still being deployed on the newest releases? I pick my new 921 Elite up tomorrow. I guess I'll find out in 25 hours.

[rudapa]

It's a major discussion item in many places, can't imagine they enjoy the "press". I guess I'm surprised there is no info about a fix from them. Everything centers around the consumer trying to come up with a fix from what I read.

[EuropeanAM]

Jaz... in regards to your questions on the Relief system, I've confirmed that OVER-TRIM limitation is strictly a PCM controlled function (utilizing data from the Trim Position Sensor). There is no hydraulic trim-angle relief in the port-side trim ram (such as was seen in earlier 2-stroke V6 products).

The Verado and several other models have utilized this method and done quite well for years. That being said- the trim sensor must function correctly in order for it to work properly.

[EuropeanAM]

Alright fellows: Let's keep this thread on track. Original topic, original poster, PRODUCTIVE or HELPFUL information about the topic.

IF YOUR ENGINE HAS A FAILURE IN THIS AREA: Get it to an Authorized Dealer. That is the ONLY way that anything will get done to rectify YOUR engine's problem. While I can appreciate the experience level of several posting in this thread (and see merit to several ideas presented), we are discussing an engine that is UNDER WARRANTY and should be corrected through the proper channels.

The latest part number for the retaining bolt is 8M0177279 (new, latest and improved Part Number).

Rants, Raves, chest-thumping, foot stomping, horror stories about other boats (whether or not true) do not help to resolve the problem(s). Keeping a close eye for any developments, but they will be tied to one specific engine/serial number.

Cleaning the thread up currently. If your post was removed, I'm sorry. If it becomes necessary again... we may have to dump the thread entirely (which doesn't help anyone).

[Blue Steel]

Too late if bolt backs out.

[NewEnglandLegend]

So how would I know which PN I have in my 2021 250 Pro XS Serial #3B040534. Thank you

Alright fellows: Let's keep this thread on track. Original topic, original poster, PRODUCTIVE or HELPFUL information about the topic.

IF YOUR ENGINE HAS A FAILURE IN THIS AREA: Get it to an Authorized Dealer. That is the ONLY way that anything will get done to rectify YOUR engine's problem. While I can appreciate the experience level of several posting in this thread (and see merit to several ideas presented), we are discussing an engine that is UNDER WARRANTY and should be corrected through the proper channels.

The latest part number for the retaining bolt is 8M0177279 (new, latest and improved Part Number).

Rants, Raves, chest-thumping, foot stomping, horror stories about other boats (whether or not true) do not help to resolve the problem(s). Keeping a close eye for any developments, but they will be tied to one specific engine/serial number.

Cleaning the thread up currently. If your post was removed, I'm sorry. If it becomes necessary again... we may have to dump the thread entirely (which doesn't help anyone).

[mikesxpress]

Go look at it and compare it to the pictures posted.

[Blue Steel]

I have personally seen two motors in the last three days that had this bolt backed out. Advised owners of same.

[rudapa]

My dealer gave me a spare, how often do you have to check it? Don, is Mercury working a fix?

[EuropeanAM]

I have personally seen two motors in the last three days that had this bolt backed out. Advised owners of same.

Did you snap a picture, perhaps- or have the serial numbers that you could PM me? Thanks!

Keep in mind that even though this appears to be a BOLT, it's function is actually more of a SET SCREW. Appearance can potentially be deceiving as the flat under-side flange of the bolt head may not seat flat against the tilt ram eyelet.

It is my understanding that the latest bolt (part number 8M0177279) has a longer threaded area. At this time- that is all the information available.