Acceleration problem of KAD300 powered Searay 315DA

[Branne]

Hi Melida , I have exactly the same problem. How did you end up fixing this issue please?

I have KAD300 and the starboard engine performs well at the beginning at 3400 RPM but after few minutes or if I try to go down to 3200 RPM the starboard engine loses rev and the supercharger kicks in and stays around 2600-2800 RPM.
My Mech changed the Turbo on that engine. Also he found a strange small hole in the aftercooler housing that leaked air. But to me it looked like a hole that was done by the manufacturer. He took it to an engineer and we closed that hole. But when I check now photos of some aftercooler online I found the same hole in these pictures. Maybe it should be there for a reason.
After changing the turbo and closing the hole in the aftercooler housing we went for a spin and the same issue remained there.
I did the service recently and all filters are new. And in order to eliminate the tanks, we used a Jerrycan of diesel and the starboard engine was taking diesel from it instead of the tanks. But same issue...
The hull is clean I think because I just did the antifoling and polishing a month and a half ago and I have been using the boat quite often.

 

[kashurst]

assuming you do not have any fault codes, if a KAD300 behaves as you describe it is either not getting enough air or not enough fuel.
check all your fuel pipes are OK and any shut off valves are actually fully open.
Take off the fuel pipe at the engine lift pump and check no blockages.
If you have the Racor 500 fuel filters remove the clear bowl and spinner unit and take out the small aluminium ball and red seal -it is an anti run back device but can play up. You don't really need it. Just close you fuel shut off valves if you are going to leave the boat for more than a month with low fuel levels in the tanks.
When you have the boat back together check for turbo air leaks - start the engine cold so the compressor kicks in and feel all around the pipes from the turbo to the air cooler. If that's not possible look on here for an excellent DIY boost pressure system and compare boost pressures. When I changed my turbos on KADs we also had to replace the O ring seal from the inlet pipe to the air cooler.

Get another engineer - pretty sure the hole is there to drain out condensation. Check the model of new turbo, the KAD 300 turbo is not the same as some of the previous derivatives of engine. Although official Volvo techs are expensive it will probably save you a lot of time and hassle to get one on board for an hour with the VODIA diagnostic box and get the exact details of how both engines are performing.

 

[QBhoy]

Hi
If you lift the tabs and trim out you will gain seriously higher rpm and speed, as you’ll likely know.

 

[Melida]

Hi Melida , I have exactly the same problem. How did you end up fixing this issue please?

I have KAD300 and the starboard engine performs well at the beginning at 3400 RPM but after few minutes or if I try to go down to 3200 RPM the starboard engine loses rev and the supercharger kicks in and stays around 2600-2800 RPM.
My Mech changed the Turbo on that engine. Also he found a strange small hole in the aftercooler housing that leaked air. But to me it looked like a hole that was done by the manufacturer. He took it to an engineer and we closed that hole. But when I check now photos of some aftercooler online I found the same hole in these pictures. Maybe it should be there for a reason.
After changing the turbo and closing the hole in the aftercooler housing we went for a spin and the same issue remained there.
I did the service recently and all filters are new. And in order to eliminate the tanks, we used a Jerrycan of diesel and the starboard engine was taking diesel from it instead of the tanks. But same issue...
The hull is clean I think because I just did the antifoling and polishing a month and a half ago and I have been using the boat quite often.

Hi Branne
It's been 9 years since I started this thread, how time flies.
In post #16 I described what I did/done to fix my problem and sold my boat a few years ago, since then no problem.
Hope you solve it.
Best regards.
Melida

 

[Branne]

Hi QBhoy
Thank you for your answer. That is true. However, I cannot see why this would help because the boat plains and I hit 3400 RPM, it is only after like 5 to 10 minutes that the RPM drops on the starboard engine. So I cannot see why the tabs position would change or affect this issue.

 

[Branne]

Hi Melida the last thing I see from your thread was this reply from you. Hence, I did not know how you solved the problem finally.
"We tried/inspected/cleaned/serviced/replaced every possible part of the engine which can cause lack of performance and minimized them with these sensors.
Any suggestions greatly appreciated. Thanks in advance."

 

[nw04jen]

Did you ever solve this as I have had exact same problem - s/b engine hasnt revved past 2500 - now sealed both superchargers as they were leaking air and again testing tomorrow but the VP engineer is fairly certain the engines are 100% and no faults - turbos brand new as are elbows - legs trimmed and tabs down, engines synced so if cant get to turbo territory tomorrow not sure whats next - clean intercooler as she been on river for 8 9 years but thats all thats left as Vodia showing every running perfectly well....

 

[Melida]

Did you ever solve this as I have had exact same problem - s/b engine hasnt revved past 2500 - now sealed both superchargers as they were leaking air and again testing tomorrow but the VP engineer is fairly certain the engines are 100% and no faults - turbos brand new as are elbows - legs trimmed and tabs down, engines synced so if cant get to turbo territory tomorrow not sure whats next - clean intercooler as she been on river for 8 9 years but thats all thats left as Vodia showing every running perfectly well....

I don't remember what I did now but IIRC injectors were faulty due to contaminated fuel and nozzles replaced then problem solved.

 

[nw04jen]

Sorry what is IIRC?

 

[Deleted member 478]

Sorry what is IIRC?

If I Recall Correctly

 

[nw04jen]

Thank you