Re: [Amel Yacht Owners] Yanmar 75HP - Cannot go over 2300 RPM

sailormon <kimberlite@...>

I had the same problem with Kimberlite. Even though when I hauled her and tried to wiggle the blades of the autoprop they seemed normal. After exhausting all other possibilities , I spend a day and rebuilt the autoprop.

Voila back to 3500 rpm. I also rebuilt the prop at about 3500 hours.

The autoprop is a sensitive beast and the slightest out of balance will kill your rpm.

Fair Winds


Kimberlite Amel Super Maramu #376




From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, January 09, 2017 12:18 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Yanmar 75HP - Cannot go over 2300 RPM



Hi Vlad and Dominique,

AutoProps require regular maintenance.  If you haven't done that in a couple of years, that may be your problem.  There are some other threads on this forum that discuss this vis a vis low rpm.  Just spinning the blades on the hub doesn't tell you much.  They can feel perfectly free wheeling, and still be a problem.

If you don't run your engine hard on a regular basis, you can get a serious buildup of carbon in the turbo and exhaust elbow.  That's the second place to look.

Let us know what you find.



From: "Vladimir Sonsev sonsev52@... [amelyachtowners]" <amelyachtowners@...>
To: amelyachtowners@...
Sent: Sunday, January 8, 2017 11:21 PM
Subject: Re: [Amel Yacht Owners] Yanmar 75HP - Cannot go over 2300 RPM



Hi Dominique,

I also have 75 HP YANMAR engine 4JH3-TE. I also can't develop more than 2200-2500 RPM.
I am discussing this problem with Autoprop.  I suspect that perhaps prop provides to much torque load.

Autoprop ask me for transmission gear ratio. The label on my transmission is gone. I requested this information from Amel. I am waiting for a reply now.

Autoprop also ask me to conduct some tests. I can't do the tests now because my boat is on hard.
I will keep you posted.



On Jan 8, 2017 10:26 PM, "songhui_ma@... [amelyachtowners]" <amelyachtowners@...> wrote:


Happy New Year 2017


Yanmar 4JH3-TE - 3600 hours - 1500 hours maintenance. 


A New Zealand mechanic replaced the injectors with Yanmar ones I provided and sourced in the US [Niemiec] Both mechanic and my US provider confirmed that it was the correct part #. 


However and since I cannot go over 2300 RPM.

The smoke is pretty transparent neither black or white. 


I browsed the internet, got a lot of ideas, but nothing which jumped out.

I suspect it is related to the Turbo - over 2300 RPM - that I have not used much and realized I should have.   


Suggestions greatly appreciated




S/V Viva 

SM #374 

Opua, NZ 




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