Volvo Engine Vibration

[daverebbettes]

Hi, does anyone have any thoughts on this. Volvo D1 30 with shaft drive. For some years the shaft vibrates alarmingly at around 2000-2200 revs and when rapidly decelerating. Alignment has been checked and double checked by Volvo engineers. Cutlass bearing checked. Engine mounts checked. They have recently tried a new fuel pump to see if this solves lumpy running but with no joy. Engineers are now suggesting changing/testing fuel injectors to see if this solves the problem. Does their analysis make sense and does anyone have another suggestion?

 

[pvb]

Have the engine mounts been removed to be carefully inspected?

 

[Skylark]

Your description doesn’t exactly inspire confidence in the so-called “Volvo engineers”.

On what basis did they “try a new fuel pump” and now “suggesting changing/testing fuel injectors”. Are you paying for their trial and error engineering?

It sounds like some form of resonance/vibration/imbalance, especially if it is not evident at lower or higher speeds. Engine mounts are a likely culprit, as suggested by pvb.

Unless you feel assured that there is logic to their next suggestion I’d also consider getting alignment checked again by someone other than a trial and error technician.

 

[[70521]]

Your description doesn’t exactly inspire confidence in the so-called “Volvo engineers”.

On what basis did they “try a new fuel pump” and now “suggesting changing/testing fuel injectors”. Are you paying for their trial and error engineering?

It sounds like some form of resonance/vibration/imbalance, especially if it is not evident at lower or higher speeds. Engine mounts are a likely culprit, as suggested by pvb.

Unless you feel assured that there is logic to their next suggestion I’d also consider getting alignment checked again by someone other than a trial and error technician.

"Trial and improvement" as my old maths professor would put it.

Sadly, these days we don't have proper apprenticeships. Has the technician been on-board when you could demonstrate the issue at sea?

 

[Bobc]

The starting point is to ascetain the following:-

Is it prop/propshaft vibration, or engine virbration (get down in the back of the boat when it's vibrating and see if the engine is trying to jump off its mounts.

If it's engine vibration, does the engine sound like it's running poorly/lumpy?

Does it vibrate in neutral with the engine at 2000-2200rpm?

Do you get vibration when sailing at the speed that causes the vibration under engine (with the prop spinning freely)?

 

[daverebbettes]

Thankyou everyone, very helpful. It is a friends boat and I will pass all comments on to him.