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Re: [Amel Yacht Owners] Rough engine at idle

Mark Erdos
 

Miles,

 

I mentioned the engine mounts first because I really think this is going to be the cause.

 

Keep in mind that anything fuel related normally effects the engine regardless of the RPM. However, it is harder to notice fuel deficiency at higher RPMs. It is easier to troubleshoot fuel issue when a load is put on the engine (smoke or lack of power).

 

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Santa Marta, Colombia

www.creampuff.us

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, January 2, 2019 8:56 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Rough engine at idle

 

 

Thanks Mark

 

I’ll check the engine mounts. Looking at the prop shaft when in gear today there does seem to be a slight misalignment by eye. 

I had the cutlass bearing replaced in the canaries so perhaps alignment has been out but somehow got worse via the engine mounts movement etc after prolonged free running of the prop shaft at speed on the long passage. 

There was also LOTS of weed on the passage. A boat we are travelling with seems to have issues with their prop after weed fouling on the trip so perhaps we also were fouled whilst running the prop shaft alternator hard which has exacerbated a prop shaft alignment issue. 

 

Hmmm

 

I’ve bled the system but only up to the injector pump. I am rather ignorant about how air might cause rough running. Perhaps if the air was just in one of the high pressure fuel lines to a single cylinder ? Wonder if this would get worse not better on higher revs. 

 

I’ll also chase the fuel line as you mention to see if there is any obvious signs of problems at unions etc. 

 

The last fuel we took on was in the canaries. Only about 50L. We don’t use much really but that which we did take on in a few places in the canaries always seemed ok and always had lots of throughput at the pumps with all the other boats. I treat with a biocide too but I could have a look at the fuel just in case. 

 

I also have a switchable double canister off engine primary fuel filter. I tried switching that to the new unused filter and the problem remained unchanged. 

 

 

Many thanks again for the helpful thoughts. Very much appreciated 

 

All the best

 

Miles

 

 

 


On 2 Jan 2019, at 15:00, 'Mark Erdos' mcerdos@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Miles,

 

A couple of thoughts:

 

Are the engine mounts in good condition? (asking this based on the issue of noise or knocking sound when running shaft alternator)

Did the problem begin after you last filled up with fuel? If so, you may have bad fuel.

Do you have a good flow of fuel all the way from the tank to the injectors (checking filters, joints for leakage, etc all along the fuel path)

Have you bled the system to eliminate air?

 

 

 

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Santa Marta, Colombia

www.creampuff.us

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, January 2, 2019 12:58 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Rough engine at idle

 

 

Hello fellow amelians
In the canaries our engine purred nicely
When we arrived in the Cape Verde’s it was a little rough on idle
On first running since the roughish Atlantic crossing (40-45kts during last 5 days) its even rougher still
I have a Perkins m65 with around 3k hours
It starts on the button but vibrates lots until the revs are increased.
Would be great to hear thoughts on any simple things I could try. I don’t think I can adjust the idle speed on the engine. Perhaps I could via the throttle cable but don’t want to make matters worse.
I’ve bled the fuel

I’m currently in Barbados where I can’t seem to find a diesel mechanic
Next stop Martinique where I’m sure I’ll find good professional
We ran the prop shaft alternator on the long crossing for 2 weeks straight. I started to notice that in the higher winds towards the end of the trip the noise from the rotating prop would change to a less regular sound at speed - almost a knocking sound
I think perhaps the prop shaft alignment needs adjusting. Perhaps the two issues are related although if so I’d imagine the vibrations to get worse with increased revs rather than get better

Any thoughts most appreciated and any pointers to good mechanics in Martinique would be great too

All the very best

Miles
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