Alpha knocking noise video.

[1985 Century Mustang]

I'm having a knocking sound by the driveshaft. Can anyone help. Video enclosed.

Mercruiser Alpha 1 Generation 1. Here is a video of it.

 

[Bondo]

Ayuh,..... Was the drive up, or down,..??
Did you try turnin' it left, right,..??

My 1st guess is u-joints,....

Pull the drive, try it, 'n see if the noise goes away,....

 

[1985 Century Mustang]

Ayuh,..... Was the drive up, or down,..??
Did you try turnin' it left, right,..??

My 1st guess is u-joints,....

Pull the drive, try it, 'n see if the noise goes away,....

Up and down. I'm gonna pull the drive tomrw.
Does it sound like Universal Joints, Kimbel Bearing or Coupler. Hope not the coupler.

 

[Dubed]

Up and down. I'm gonna pull the drive tomrw.
Does it sound like Universal Joints, Kimbel Bearing or Coupler. Hope not the coupler.

As Bondo said, it sounds like u-joints. While drive is off, this is the time that you should inspect all other components and service as necessary.

 

[Bt Doctur]

u joints or a destroyed gimbal gearing. When was the drive removed for service last?

 

[1985 Century Mustang]

u joints or a destroyed gimbal gearing. When was the drive removed for service last?

The boat was rescued from my friend's driveway. And it hasn't been run for at oeast 12 years. I'll pull the stern when the rain lets up, I'm banking on a bad u joint.

 

[1985 Century Mustang]

I pulled the Sterndrive and it still makes the same noise. So I'm guessing the coupler or flywheel.

 

[1985 Century Mustang]

I may try the timing and octane boost like mentioned in an older thread

 

[dubs283]

I pulled the Sterndrive and it still makes the same noise. So I'm guessing the coupler or flywheel.

Could be, but.....

I agree with bondo's post in one of the threads you hijacked, most likely crank/rod bearing(s). Ime with a confirmed (drive removed) engine noise/knock as prominent as yours the issue most often is a lower end bearing

Either way the motor needs to come out and further inspection performed

 

[1985 Century Mustang]

Thanks, FWIW I'm not hijacking a thread, merely I'm adding to a thread with the same issue, it's like a collective if you will.

 

[1985 Century Mustang]

I'm going to try the timing and possibly higher octane( maybe octane boost) Like I read in another old thread w same issue

 

[Bondo]

Thanks, FWIW I'm not hijacking a thread, merely I'm adding to a thread with the same issue, it's like a collective if you will.

Ayuh,..... No, it's Not,..... As I've said, read, 'n follow our posting rules, 'n guidelines, the link is in my signature, if you wish to be a member of iboats forums,......
In there you'll see, that threads over 90 days old, are closed to any posters, other than the original poster,.....
This is yer last warning,.....
Keep doing it, 'n I Will ban you,.......

 

[1985 Century Mustang]

Could be, but.....

I agree with bondo's post in one of the threads you hijacked, most likely crank/rod bearing(s). Ime with a confirmed (drive removed) engine noise/knock as prominent as yours the issue most often is a lower end bearing

Either way the motor needs to come out and further inspection performed

This is a fairly new block with only 40 hrs or so on it. The original owner had replaced the block, and he only used it for a short period of time. So methinks not a lower bearing. Just saying.

 

[1985 Century Mustang]

FWIW I actually cleared out all the heavy rust in the elbow exhaust riser and the knocking changed slightly. I'm trying everything before yanking the engine. I'll pull the starter and see how flywheel is also. Timing and octane boost is next. I'm going to pickup an alignment tool also. To see how it is/was aligned.

 

[Grub54891]

Welp. We had one in the shop a few years ago. Very similar sound. Testing/checking things came up empty except the noise was definitely from the flywheel area. Pulled motor, removed bell and found the po had worked on it and the flywheel had come loose. Torque specs and locktite are your friend in that case.

 

[1985 Century Mustang]

Welp. We had one in the shop a few years ago. Very similar sound. Testing/checking things came up empty except the noise was definitely from the flywheel area. Pulled motor, removed bell and found the po had worked on it and the flywheel had come loose. Torque specs and locktite are your friend in that case.

Hey man thanks so much for that info, after all the research I was suspecting a flywheel also. FWIW The engine coupler was clean and drive shaft spline was good, the alignment was fine as well So I guess I can count out a coupler hopefully. Needless the engine has to be removed anyway.

 

[1985 Century Mustang]

I'm going to double check the cylinders to see if they are all firing, I'll also do a compression test and check out the timing...Couldn't hurt before I pull it

 

[1985 Century Mustang]

I'm going to inspect The Exhaust Water Flapper also.

 

[1985 Century Mustang]

Water flapper was missing from inside the riser, so that wasn't the knocking sound, needless I'm gonna have to get a replacement.

 

[1985 Century Mustang]

Targeting the Flywheel soon. I'm gonna remove the engine. Is there anything I should check or change when the engine is out?