Crazy shake vibration

[MikeyArriva]

Hey all, so I went to take the family for one last cruise to see some leaves changing color down the river. I left the dock all seemed ok besides a slight vibration. Got up on plane and across the lake with no issue. Slowed down at the river and all of a sudden the boat started shaking and clanging from the back. I throttled up a bit and it went away i slowed down again to turn around and it came back really bad. I was going to float to a dock but wanted to see what happened if i throttled up again and sure enough it went away. So went back across the lake fine and throttled down just out from the dock with no shake. Then i turned a bit and it came back. I got to the dock shaking and put in reverse to bring the back end in and something was just smashing back there. got it stopped walked it onto trailer and came home. pulled outdrive off assuming something was wrong with cv joints but they seem to be perfectly fine. There was a small little metal piece sitting in the bellows it was almost a c shape but broken and seems like it was a full circle at one point. was the only piece i could find. its like it would probably be the diamater of the shaft going through if it was whole. Gimble is smooth, I see no wear in the bellows. Any ideas what i should be looking for?? maybe some more info i could give? I am sorry i am trying to learn as i go here and even searching online hasn't shown me anyone with similar issues. thought i would take a chance here before going to marina i can't afford right now. thanks in advance

 

[badrano]

What your setup...Merc/Volvo?

The only thing I can think of is the C-clip that holds the cross bearing off the yoke or drive shaft. At lower speeds it could be moving around just enough to through things out of balance.

 

[MikeyArriva]

sorry mercruiser 5.0 alpha one gen 2

 

[MikeyArriva]

i will see what that is and see if i am missing it lol

 

[badrano]

Look up part # 805536A2 or 865493A01.

Could you post a pic of the piece?

 

[MikeyArriva]

sorry its an 89 so i guess its a gen 1

 

[MikeyArriva]

and again i messed up after you said c clip i thought maybe until i remembered what a c clip was i will try and post a pic

 

[MikeyArriva]

[No message]

 

[MikeyArriva]

its metal and has a couple ridges assuming it was a complete circle at one time

 

[badrano]

sorry its an 89 so i guess its a gen 1

No worries. Is it an Alpha 1 or Alpha 1 SS? Looking at Merc parts catalog, there are couple different part #'s, but same basic idea for the C-clip. Looks like plain Alpha 1 may have a grease zerc on it.

 

[MikeyArriva]

def not a piece of a c clip that i found in the bellow

 

[MikeyArriva]

let me know if pics showed up above trying to go from phone to computer lol. it is an 89 arriva 2050 i believe it is just an alpha one. i have never heard of the ss until now

 

[MikeyArriva]

do you have an email i can send a video too? the joints seem in great shape, no play, smooth turning, I expected something to be noticeably broken to be smashing so hard. I don't know where this little piece came from

 

[badrano]

def not a piece of a c clip that i found in the bellow

I would agree. I don't see any part in the bellows drive line that has ridges like that.

 

[nola mike]

Is your driveshaft turning smoothly? I'd pop the top cap of the drive, and also check the oil. I don't recognize that piece...
Also might want to run some water to the engine and start it without the drive on there.

 

[zellerj]

Was the lake weedy? Sounds like what happens when a bunch of weeds or plastic bag or rope or something gets around the prop and causes it to be out of balance. Usually a short burst of reverse clears it. Sometimes just putting it in neutral clears it.