Motor vibrating on land

[1989SeaRay]

I have a mercruiser 454 that I just finished rebuilding. I fired it up in my driveway and around 1500rpms the whole boat starts to shake. I do not have the drive engaged when this happens. Everything on the motor is basically new including the harmonic balancer. There is also a slight ticking that I haven't been able to track down yet. All of the cylinders are getting spark. Any suggestions on what could make the boat shake?

 

[betayv]

Re: Motor vibrating on land

what about you the engine mounts are they new?. I will think about harmonic balancer but you said is new. check the mount.

 

[1989SeaRay]

Re: Motor vibrating on land

Engine mounts are new also.

 

[CheapboatKev]

Re: Motor vibrating on land

how bad did she shake before the rebuild?

 

[1989SeaRay]

Re: Motor vibrating on land

That's the bad part...it didn't

 

[BaileysBoat]

Re: Motor vibrating on land

Back to basics, but double check the firing order?

 

[Shrub88]

Re: Motor vibrating on land

Everything on the motor is basically new including the harmonic balancer.

454 is externally balanced.

Did they give you a 427 balancer by mistake?

Was the flywheel changed?

 

[1989SeaRay]

Re: Motor vibrating on land

It is a 454 8" O.D. Harmonic balancer. The flywheel was not in bad shape so I reused it.

 

[Bt Doctur]

Re: Motor vibrating on land

double check the firing order by physically tracing each wire from the cap to the plug
Ask me how I know

 

[deves3000gt]

Re: Motor vibrating on land

I would have to agree with BT i did the same thing in my truck and at about the same rpm's it shook pretty good. and i only had two wires mixed up.