270 SLX noise in turns

[Bill Clark]

Just bought a 2008 270 SLX with the 496 mag engine and 260 hours.
At slow speeds, as soon as I start a turn, a distinct loud rattling noise starts but stops when I straighten back out. It happens in both directions. Any ideas?

 

[GoFastr]

It may be the universal joints on the main shaft from the engine to the sterndrive. My noise was more of a knocking sound when I had them replaced which solved it.

 

[LG111]

Ujoint and gimbal bearing. Ujoint knocks and bearing has a metallic whine when worn or water intrusion.

 

[Bill Clark]

Ujoint and gimbal bearing. Ujoint knocks and bearing has a metallic whine when worn or water intrusion.

Thank you...much appreciated.

 

[GoFastr]

Once you remove the stern drive you can easily check things out. The shaft will be visible along with the u-joints and yo can check them for proper movement. This will also give you an opportunity to check the gimbal bearing, bellows, shift cables, etc.

My dealer wouldn't buy just the u-joints and press them back into the existing drive shaft, they purchased the entire assembly which was almost $1k. If it turns out to be your u-joints one of the critical factors is getting the proper torque and clearances on the retaining nut set properly when reinstalling everything. After that, you must do an alignment procedure when reinstalling the stern drive. In my case, the dealer didn't torque the drive shaft nut enough and it was left a bit loose causing the shaft to walk back and forth and by the 2nd trip out I couldn't even get the boat off the trailer because it had ate out my coupler.

Not wanting to scare you with my horror story but just passing along a few things to double check or at least remind your mechanics about.

Good luck and happy boating!

 

[scoflaw]

U joints can be easily replaced without removing the pinion shaft. There is an automotive joint that is an exact match to the Merc joint, both can be bought for less than $40