2015 Mercury 250 Pro XS Rattling Noise

[bobby.leejr]

2015 250 Mercury Pro XS
Serial # 2B122319

Water Pressure at Idle: 1.0
Water Temperature at idle: 119-120

I can't remember the exact water temperature and pressure but they were in spec.

I have a 2015 250 Mercury Pro XS that is making a rattling noise from about 3900-4200 RPMs. Adjusting the trim will make it stop. It appears to be worse when the motor is trimmed down and there is more of a load. Does anyone have any idea what this could be? Motor runs very well other than the rattling.

Video of the noise:
https://www.youtube.com/shorts/XSqASvIwQ2I

Video on the muffs:
https://www.youtube.com/shorts/-WHQLBZRMTg

[JOE54]

sounds gearcasey to me drain gear oil look for metal debri

[JYoung022]

Your definition of rattling may different from mine, but I had a similar issue with the "plastic" covers over the lower bracket mounts. Was very rpm sensitive. It was more of a buzzing noise to me but loud enough to get attention. I removed them and the noise was gone. Ended up putting small pieces of double sided tape at the corners and issue solved. May not be your problem but maybe something to check.

[bobby.leejr]

One of the engine mount covers is cracked.

[bobby.leejr]

I took those off and it is still doing it. It seems to get worse under more load.

[bobby.leejr]

Drained the lower unit oil. It’s clean as a whistle.

[EuropeanAM]

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!

[bobby.leejr]

Sorry, Don. I updated with the appropriate information.

[JOE54]

Drained the lower unit oil. It’s clean as a whistle.

thats good , remove cracked cover and go for a ride

[bobby.leejr]

I took engine mount covers off and it’s still doing it. Although not near as bad without my 200lb nephew in the boat.

[EuropeanAM]

Did you check the lower cowling to driveshaft housing rattle that's described in the FAQ Section?

[Z7bloodtrail]

Check hinge bolt on power poles, Should be checked every 100 cycles . My 10 ft blades had a rattle at same rpm range, was looking at engine also drove me crazy. Tightening pole hinge bolts fixed it.

[EuropeanAM]

Wow....