Volvo penta kad42 - speed problem - please help...

[Supercose]

Dear All,

I have 1995 Wellcraft Martinique 27 with single diesel Volvo Penta KAD 42.

Normally boat sails with 23-26 knots gps speed with 3000 - 3300 rpm with maximum speed of 33 knots at 3500 rpm.

Last week performance of the boat was very good but this week I faced with a strange problem.

At marina, in neutral (N) gear, when I give throttle, engine goes up to 3800 rpm which is quite good.

However, at the sailing, when I give full throttle engine stucks at 2000 rpm with 8.9 knots gps speed and never go more.

Also there is no any white or black smoke.

I have removed turbo, compressor, intercoller, injectors and cleaned them and connect again however nothing changed.

I checked the quality of the diesel also it was good.

I checked cable/wire of the throtte arm and it was also good and normal position.

What could be the problem ?

Where do I have to look and check ?

Waiting your helps and recommendations.

Kind Regards

 

[targa31]

Hi,

Is the compressor coming in ok? Should be whining away at 2000 revs.

If so have you checked for air leaks?

I have 2 of these and both have developed air leaks on the compressor gasket in the past. Also check all around air supply for leaks (intercooler etc).

Presume the fuel filters have been checked/changed?

Other items I have read about in the past on this forum which may cause the issue:
problem with outdrive
problem with props
air leak on bleed screw on secondary fuel filter
flap in the air intake sticking/broken and letting air pass

For clarity I am not a mechanic just have some experience with these engines!

Hope you fix it.

 

[Hoblands]

Interesting, I'm having the same problem with a Jeanneau Leader 805 running a Kad 43. Will rev up to 4000rpm at idle but gets stuck at 3000rpm under load giving a max speed of 23.5 knots (should be 30+), prop, drive and compressor / turbo checked, major service carried out a couple of weeks ago and yet to try her again at sea but not too optimistic as everything seemed A1. Checks for air leaks on the next outing then I think...

 

[targa31]

Air leaks can be checked alongside.

For compressor checks run at 2300 revs and turbo at 3000.

Feel around pipe work for escaping air and use a small piece of paper to locate exact leak if required. 2 bits of safety. One watch for moving bits on the front of the engine. And secondly which I learnt the hard way is use ear protectors or you may end up with ringing in your ears for a bit!

 

[vandy]

Engine rev is often related to either poor fuel flow; or prop issue. whilst there are many more issues to think about (compressor, leaks, turbo kicking etc.) but I would check with basic things -

Revving at idle doesn't give any indication of how engine performs under load - Also, are you sure your engine isn't too much under load (badly fouled hull?)

 

[Bandit]

Both of you how clean is your hull and props, any weed growth or barnacles, any water in the bilge?

 

[captaindan]

Airflow issue maybe or Something more sinister

 

[Hoblands]

Props (duo props) = Brand New
Hull & Leg = Anti fouled at the same time as service 2 weeks ago

Sounding like an air leak so I will check on the next visit and report back...

Paul