alpha one gen 2 vibration clunking

Bondo

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71,214
are there any kind of ruber mounting on the back mounts mine look to be just a solid mount nothing to absorbe any natural engine vibration.,

Ayuh,..... Welcome Aboard,..... The rear motor mounts are rubber bushin's in the flywheel cover,....

If they've failed, it could be aluminum to aluminum,....
The front mounts are also rubber bushin's, 'n pin style mounts,....

Im going to jave to figure out how to get this all apart

In my signature is a link for Don'S Adults Only Section, in there are links to the factory Merc manuals,....
Feel free to look 'round,...
 

heath454

Seaman Apprentice
Joined
Mar 18, 2014
Messages
49
thanks everybody for you help so far. bondo i had the engine out. mounts and rubber looked ok. not cracked or deteriorated in any way. tonight i did some more diagnostics on the hose . first let me say. there is actually about .035 thou of up and down movement in the gimbal ring at the bottom. i did find that the ring was moving on the upper pivot shaft. were the two bolts bascily clamp the ring to that pin.. i tightend them up and took alot of play out of the steering....... so i would start the engine trimmed down. run the rpms up in gear then turn the lower unit to the right and make the ujoints chatter. then i would take a bar and raise up the entire unit taking all of the drop out of it. this did not change the ujoint chatter at all.. no difference what so ever. so i then realized this thing only chatters really bad when turning to the right. so i looked at how far it turns right and how far it turns left... turns another 1/2 to 3/4 inch further to the right thus making the ujoints chatter. so what would cause it to turn further or to far to the right. is there a steering cable adjustment???? is this due to play in the pivot pins of the gimabl bell housing.????? or something in the steering linkage worn out.???? i have also noticed that the prop shaft and maybe the prop is bent, there is alot of wobble in the prop when its turning.. so i removed the prop and let just the prop shaft turn .. yep its not running true ethier. looks to be bent to me.... boat has a rampage 14x20 stainless prop on it. it has hit a few things in the past, has some pretty good nicks in the blades. so im thinking its def bent. not sure what kind of issues that can cause but..... last thing i though about was timing. the boat is always hard to start and kinda slow at idle.. i build motors several of them and build mild performance engines so when i say slow i mean i could tell the timing was off... sure enuf. tag says 8 degrees and it was bairly 2.. so i bumped it up to about 11.. i run 93 octane in it so maybe i can squeez just a llittle more advance out of it. but i will be taking timming light and wrench with me to the lake for some adjustment if needed. . it does start alot better now. boat would run 47mph with no timing so as long as it dont spark knock i may get 50 out of it now. tach runs between 4800-5000 at top speed .wonder if i should change
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Bent propshaft. Maximum allowable is 6 thou, which you would barely see. If you're seeing a wobble, it's way too much. Shaft has to come out and either get straightened (I've done a few quite successfully with a set of Vee blocks and a press) or replaced with a new one.

Chris.....
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
Yah,

The cost of the tools is just part of it, the parts themselves end up costing more than you would think. Most often, if you have to go that far yourself, it is cheaper to get an SEI and, unlike if you work on it yourself, you get a 3 year no fault warranty.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Hey Chris, that takes it apart... what all do you need to assemble properly if you replace the shaft?

Tools to assemble if you replace the shaft.
Drive shaft adapter, pinion nut tool, cover nut tool.
Forgot to mention in the earlier list, factory service manual. :D

Chris. ....

EDIT: And a torque wrench for up to 200ft-lb
 
Last edited:

heath454

Seaman Apprentice
Joined
Mar 18, 2014
Messages
49
so what will a bent shaft cause.. and how bad does it have to be to consider the cost to change it.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
so what will a bent shaft cause.. and how bad does it have to be to consider the cost to change it.

Vibrations, which can lead to bearing failure, and depending on how bad, coupler and yoke could also suffer. The vibrations may even cause other boat hardware to come loose.

How bad? 0.007" is the book spec.

Prop.PNG
 

heath454

Seaman Apprentice
Joined
Mar 18, 2014
Messages
49
ran the boat several hours off and on during this 4 day camping trip.. advancing timing helped it run alot better. tach will actually run up to 5200 and just almost reach 55mph on spedo. 47 was top speed before..backed timing back to 9 -10 degree. thought i may have herd a little spark knock... still runs great. plenty fast. and comes out of water good.. vibration still there gets worse and turns into a chatter when you turn it .. i am stumped..makes no since to me
 

heath454

Seaman Apprentice
Joined
Mar 18, 2014
Messages
49
yes replaced u jonts. but i swear it has something to do with the ujoints of the shaft or somthing.. no other reason why is would have so much vibration in it and here them chatter when you turn it.
 

heath454

Seaman Apprentice
Joined
Mar 18, 2014
Messages
49
hey guys still having same issue.. i am trying to upload a video. of what this thing is doing
 

09TNRT

Petty Officer 2nd Class
Joined
Jun 26, 2017
Messages
104
I'm no expert on boats at all but that really does sound like ujoints. You said it's always done that, any chance that the PO had ujoints put in and got the shafts out of phase or tweaked the yoke or something? I don't see that shaft being bent but who knows. The vibration on hard turns AND when you trimmed up to me says its something to do with that driveshaft. Unless there's another piece to the puzzle that my newbie self hasn't learned yet.
 
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