vibration when accelerating... ideas what it is??

sarabande said:
serious question from a raggie...

Is it possible for cavitation to occur only at a very narrow rev band, and/or when under hi-torque loading ? Analogous to resonance when accelerating in a car.
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In practice NO, blade tips approaching supersonic only at WOT, if it does occur then somebody screwed their sums up.......
 
Latestarter1 said:
I have a Fluke, it is what comes with territory when you employ decent engineer.

Main dealer service tec's are not engineers.....................No point asking tec for report when it all goes horribly legal.

People always want to sort out problems on the back of a fag packet, certain you have people wanting to pick his brains for nowt!
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If you want to sort this one with your fluke in sure your services would be greatly appreciated,

For the record Essex boatyards are not selling this boat , but supplied its current owner which has this problem.

It's the port engine, starboard motor is fine so it can only be a rotational issue, it does it when accelerating from idle, it's been tested with each motor in turn, starboard motor is fine, it's the port one that appears to be the problem.
 
If these are D9 Engines then some were built with the oil cooler thermostats omitted.
This caused the g/box oil temp to rise to temps that lead to g/box failure.

Certainly make sure the g/b oil temp is enabled on the digi disps and check/monitor.

Incidentaly, these g/bs / oil coolers cant be run without a thermo.
 
splosh said:
If these are D9 Engines then some were built with the oil cooler thermostats omitted.
This caused the g/box oil temp to rise to temps that lead to g/box failure.

Certainly make sure the g/b oil temp is enabled on the digi disps and check/monitor.

Incidentaly, these g/bs / oil coolers cant be run without a thermo.
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D12 800 Clive but yes good point I know where your coming from, I remember the oil grade issue too you had with your v drives on your motors.
 
Yes, youve got a good memory. That was ages ago and I must say a great improovement since Twin Disc recommended the Mobil spec oil at the first service.

In any case I would certainly question the oil spec in this topic and check what the gearbox manufacturer recommends.
 
volvopaul said:
If you want to sort this one with your fluke in sure your services would be greatly appreciated,

For the record Essex boatyards are not selling this boat , but supplied its current owner which has this problem.

It's the port engine, starboard motor is fine so it can only be a rotational issue, it does it when accelerating from idle, it's been tested with each motor in turn, starboard motor is fine, it's the port one that appears to be the problem.
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Very reason why each to his own, and I would run a mile. No desire to start learning about Green engine issues, will stick to the stuff I know!
 
Ive just had another one of these today on a Princess V53 with 800s.

When accelerating hard there is a sudden shudder through the boat. Port side only again. The mod is usually done by the ZF dealer here who changes something in the valve block and sometimes the clutch plates.

I think you would get the same from the stbd side when throttling hard in astern but Ive never tried it.


I think this is the 6th one now, all have been fine after the mod.
 
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sgoodwin71 said:
i rebuilt the boat in conwy last month, after coming back from the med on transport.
the prop was bent then & was not repaired.
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There is a boat mix up here. The Sq58 recently built up in Conwy, ex Mallorca, now in N Ireland, is the boat in post #1 and NOT the Swanwick-lying boat in #14 that is currently vibrating and currently under discussion
 
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