Mercury 9.8 vibration

[LakeJulia]

I have a 1985 Merc 9.8 which I use on a 14' aluminum V-hull. At full throttle the engine vibrates - curiously when I give the tiller handle a few quick back and forth shakes the vibration stops and it runs fine. It has always done this sort of thing since my dad bought it new back in '85. Now that I have inherited this rig I want to see if there is something I can do about it. Uses the OEM prop and engine seems to run good otherwise. Engine has been fairly well maintained. Hmmmm? Any ideas out there

 

[Fouled Plug]

Re: Mercury 9.8 vibration

Hmmm. Wonder if there's a bushing in the motor swivel assembly that's causing the shimmies. Bad motor mount? It's afraid of the water?

 

[Waco]

Re: Mercury 9.8 vibration

Is it a really bad shake like the ones at the quick mart? Okay, bad joke. How bad does it shake? When you have it out of the water, can you move the motor with your hand? by shaking it? That would be where I started to look. How about this, while your running the boat, and the motor is shaking, can you tell if the motor mounts are moving with the shake, or is the motor mounts staying put? Sounds like bushing, swivels, something like that. Hope you get it fixed, you wouldnt want that thing to jump off the boat!