I'm picking up bad vibrations

[lartamax]

I have just had a completely new 4 stroke 80 Hp outboard installed to replace my old 2 stroke. All is well apart from the vibrations. This starts at around 6 knots and continues to grow as you accelerate. I can feel the vibrations in the drivers seat from around 10 knots upwards and even at cruising speed (15 knots) the vibration which seems to gradually spread throughout the boat coupled with the hum that makes your ears pop would pretty much put you off going out.
Any suggestions for causes or solutions greatly appreciated.

 

[sarabande]

Sounds like cavitation for first cause.

Any dings on the prop blades?

Is the prop size a standard one for the boat ?

or

Is o/b secured firmly to transom ?

Does the engine run smoothly (no vibes) if you rev it up out of gear ?

Any hull panels resonating ?

A loose component (e.g. pipe work ) in a compartment ?

Did you install new control cables - are they routed clear of everything ?

 

[lartamax]

Al new

Sounds like cavitation for first cause.

Any dings on the prop blades?

Is the prop size a standard one for the boat ?

or

Is o/b secured firmly to transom ?

Does the engine run smoothly (no vibes) if you rev it up out of gear ?

Any hull panels resonating ?

A loose component (e.g. pipe work ) in a compartment ?

Did you install new control cables - are they routed clear of everything ?

re above,

Engine, prop, control cables all new and fitted by supplier.
I haven't tried revving up out of gear but have a day off tomorrow so thats one of a few items I will check.
No loose pipe work.
This starts at the rear effecting the structures closest to the engine then spreads as you increase speed moving up the boat into the driver seat etc.
The engine is very slightly vibrating at tick over speed.
The panels nearest the engine are clearly vibrating if you rest your hand on them.

 

[iangrant]

Play

the beach boys at full volume

sorrry, runs for cover

Ian

 

[Solitaire]

re above,

Engine, prop, control cables all new and fitted by supplier.
I haven't tried revving up out of gear but have a day off tomorrow so thats one of a few items I will check.
No loose pipe work.
This starts at the rear effecting the structures closest to the engine then spreads as you increase speed moving up the boat into the driver seat etc.
The engine is very slightly vibrating at tick over speed.
The panels nearest the engine are clearly vibrating if you rest your hand on them.

Sorry, I don't understand why you are asking the question on here. You say it is an all new installation by the supplier. Don't go searching about and touching things that are surly under warranty.Call the installer and say you have problems and get him/her/it down and take the boat out for a sea trial with him/her/it on-board. Get installer's opinion first.

If you then have an issue then look to see what redress you might have.

 

[tinkicker0]

Sounds daft but you don't have a short shaft motor on a long shaft boat do you?

 

[Kawasaki]

Any suggestions for causes or solutions greatly appreciated.

Can you trim the engine out a tad and try again, then report back?
Unless you have tried this already!
I ask because I have come across this symptom before.

But as Solitaire posted if the rig is new the suppliers should sort the job out.

Plus what make/ model is the boat and what make engine please.

I would suggest there is a mounting problem of some sort as opposed to an engine prob.

An incorrect prop or even the motor attached at the wrong height etc shoild not induce vibes
Cavitation or airiation yes possibly, you might suffer these phenomenon in that case.

Oh! and can you feel the vibes at tickover?

 

[omega2]

Are we firing on all cylinders??

 

[Kawasaki]

Are we firing on all cylinders??

You been talking to my swmbo?

 

[lartamax]

Thanks

Thanks all for the help.
I don't plan to go poking about at anything as yes it is still under warranty. I am only planning simple things like revving while out of gear or as Kawasaki says trim up and try that. Otherwise I will be leaving all to the dealer. My own boating knowledge is very limited so I posted here to have some idea of possible problems etc before going to talk to the dealer. I just prefer to have some background knowledge given the expense of a new engine. Not to suggest that the dealer would be in any way unscrpulous as they have been nothing but helpful to put it mildly. I just prefer to do some background reading etc beforehand.

 

[lartamax]

Just off the boat trimming up or down makes no difference plus the vibration is still there out of gear.

 

[sarabande]

as suggested - engine vibration looks more likely as the cause of the panels resonating. But again, this phenomenon is usually pretty specific to a limited rev range, so it looks fundamental to K's suggestion of the engine mounts producing an eccentric and atypical vibration which is transmitted to the whole boat.