Knocking noise at low idle

[Mhemry]

I habe a 3 year old outdrive that just started making a knocking noise at low idle. I habe taken everything a part and gimble bearing and ujoints seem good and tight. Where it seems like there is some play is at the yoke where the ujoint assembly attaches to the bearings inside the upper unit. I took off the top cover and see no damage to anything there. I am posting a video of what I believe to be qhere the sound is coming from. I also did this with the top cover off and it seems like the vertical shaft with the bearing is wobbling. Any insight is greatly appreciated.

 

[Scott06]

I habe a 3 year old outdrive that just started making a knocking noise at low idle. I habe taken everything a part and gimble bearing and ujoints seem good and tight. Where it seems like there is some play is at the yoke where the ujoint assembly attaches to the bearings inside the upper unit. I took off the top cover and see no damage to anything there. I am posting a video of what I believe to be qhere the sound is coming from. I also did this with the top cover off and it seems like the vertical shaft with the bearing is wobbling. Any insight is greatly appreciated.

Picture and video posting isn’t working at moment post on YouTube or other file sharing site then put link here. Yoke should have no play in it. Did the nut holding the driveshaft in get loose ? Should have an azz load of torque on it

U joints can be hard to diagnose I just changed mine they were the original perma lube ones with 350 hrs felt
Smooth but when I took them out one or two crosses on each had ridges worn in and dark grease.

Not sure what drive you have but gen one drives use a moog 315g or equivalent gen two and I think bravo use a moog 344 or equivalent

They aren’t much I would change them if you do bearings on yoke

 

[Mhemry]

Picture and video posting isn’t working at moment post on YouTube or other file sharing site then put link here. Yoke should have no play in it. Did the nut holding the driveshaft in get loose ? Should have an azz load of torque on it

U joints can be hard to diagnose I just changed mine they were the original perma lube ones with 350 hrs felt
Smooth but when I took them out one or two crosses on each had ridges worn in and dark grease.

Not sure what drive you have but gen one drives use a moog 315g or equivalent gen two and I think bravo use a moog 344 or equivalent

They aren’t much I would change them if you do bearings on yoke

It is an Alpha 1 Gen 1. When I removed the top plate and wiggled it the noise was gone. I am not sure what that vertical shaft with the top bearing on it is called. But that has play in it side to side.

 

[Scott06]

It is an Alpha 1 Gen 1. When I removed the top plate and wiggled it the noise was gone. I am not sure what that vertical shaft with the top bearing on it is called. But that has play in it side to side.

Can’t tell from the video if it is backlash in the gears or if it is play. Some backlash in gears is normal. With top cover removed the vertical driveshaft will move as top cover locates the upper bearing. With cover off there is only one bearing on bottom so movement is expected

 

[Mhemry]

Can’t tell from the video if it is backlash in the gears or if it is play. Some backlash in gears is normal. With top cover removed the vertical driveshaft will move as top cover locates the upper bearing. With cover off there is only one bearing on bottom so movement is expected

Makes sense. I will replace ujoints as you suggested.

Thanks!

 

[Scott06]

Makes sense. I will replace ujoints as you suggested.

Thanks!

Can you wiggle the yoke side to side ? That’s what I could not tell in video ? If there is play there , not backlash you have an issue with the bearings

 

[tank1949]

don't know how old boat is or mounts' condition. You may want to check alignment, if you haven't already. Then buy cheap stethoscope and listen. You can feal U-joints for excessive wear and examine for rust. Obviously replace if bad. You can also feal roughness in the gimbal bearing.