Mercruiser 1,7 DTI 120ps, Askeladden 645 Beetle

[Swe]

Dear expert community,

I am a Swede living in Denmark, and I hope you will accept a question formulated in English ;-)

I have a beautiful Norwegian boat, Askeladden 645 Beetle (ca 1500 kg) from 2005.

Motor onboard is Mercruiser 1.7dti with 120ps.

I bought the boat 3 years ago, and have since the beginning had some challenges you might be able to help me out with...

The challenge:
After a few months, the motor started showing signs of not wanting to accelerate correctly.
a) The motor always starts perfectly
b) with no gear in, it revs well to the 4500 U/min or so that it should be able to reach
c) with gear in, the motor will start accelerating until 2000 U/min or so and then stay on that rev for everything between 5 and 20 seconds, before the whistling from the turbo can be heard and the acceleration comes.
d) once the acceleration comes, all is well except for the fact that the motor will not reach more than 3500nm.

Done so far:
1) Verified, the boat is clean underneath
2) use professionals...Each year the mechanics have tried different things to fix the problem (and have also given the boat correct winter service).
3) The turbo loads the right pressure, (measured by mechanic) and the waste-gate operates as it should
4) Propeller has been changed from 17 inch to 15 inch.

None of this has helped...

Remaining guesses/tips from my mechanic in Sweden (who honestly has said that he does not know what the problem is):

a) Maybe the diesel pump is not giving enough diesel ? (but he means this would be strange since the motor always runs ok after the 5-20 seconds "wait".
b) Maybe the turbo needs a reconditioning after all (in spite of good charge pressure)

If any one out there has experiences to share, I would be forever grateful, before I change both turbo and diesel pump ;-/

Thank you all in advance,

Frederik

[Leuchtturm]

Have you ever changed the diesel filters? I had a similar problem not quite as strong but no final speed more there was the diesel filter clogged.

[Swe]

Thanks Martin, yes all filters are exchanged with every winter service (just checked the invoices ), the problem must be hiding somewhere else.
As extra info,
1) there is also no bad exhausts (no black smoke).
2) if I trim the motor so that the propeller is almost out of the water while waiting for the engine to go from the 2000 U/min and upwards, the motor will start accelerating, and then I can lower the propeller and get the acceleration.

BR

Fred

[Swe]

Dear all,

are there any other cool tricks to be tried ? I will at least go through the entire diesel fuel feed line, from tank to cylinders... let's see what that might bring...

BR

Frederik

[Raili]

..I would check if there are any air bubbles in the fuel line to the engine during operation especially at acceleration. Another good idea would be to check youtube videos on the 1,7 dtci engine cars (Astra,..). Maybe somebody already had the same problem in a car?

[Bushrider]

Feed the motor from a separate tank .
You need to guide the return line into the same tank otherwise it might be empty within minutes and your diesel went back to the main tank .
This way you can exclude the tank and the supply line .


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