KAD43 lagging port engine video

[Jonmendez]

You can't plane with three propellors (see the video).
I know this from first-hand experience

And i can assure you that you can!

 

[[2068]]

And i can assure you that you can!

Ok, but looking at that video again ... if that's because he's lost a propeller, I will eat my laptop.
A slipping propellor, maybe.

 

[DavidJ]

Thanks for you interest in solving my problem
From snorkling at our destination I definitely have all props.
Also I've had a slipping prop on a previous boat and the engine roars away with little drive like a car slipping clutch.
My money is on stuck turbo or leaking compressor
Cheers guys
David

 

[A_8]

Looking at your video again and there is indeed an additional lag/hesitation which given the rpm suggest it's something related to the compressor. I also noted as have been pointed out that you are a few 100 rpm off to start with so what's up with that?
What rpm are you getting on each engine at wot?

 

[DavidJ]

What rpm are you getting on each engine at wot?

Well spotted on the 100 rpm down but I put that down to driver error. Our marina in Spain is on a canal system and you have to chug out at 3 knots for 10 mins (with traffic) so might be a tad uneven on the throttle when I reached the harbour mouth. (It's good for a gradual engine warm up though)

I haven't done a wot for some time but happily cruised at 22 knots at about 2700 rpm (from memory!) with both rpm meters reading the same and throttles at exactly the same position.

Actually I've just watched the video again and the rpm is down all the way through not just the beginning so my assumption of driver error can be discounted.....indeed what is going on??

 

[Racingfrank7]

Other thing to check is with engine switched off check that full throttle at the helm is full throttle at the pump.
Also check the calibration of your rev counters.

 

[DavidJ]

Thanks Frank, I understand where you're coming from but when you're at the helm you can "feel" that there is a problem and that it's not just a cable length or rev counter calibration issue. You can "feel" the port engine struggle.
Cheers
David

 

[A_8]

Well spotted on the 100 rpm down but I put that down to driver error. Our marina in Spain is on a canal system and you have to chug out at 3 knots for 10 mins (with traffic) so might be a tad uneven on the throttle when I reached the harbour mouth. (It's good for a gradual engine warm up though)

I haven't done a wot for some time but happily cruised at 22 knots at about 2700 rpm (from memory!) with both rpm meters reading the same and throttles at exactly the same position.

Actually I've just watched the video again and the rpm is down all the way through not just the beginning so my assumption of driver error can be discounted.....indeed what is going on??

You should really do a wot test and the throttles being in the same position don't say much. Make sure they bottom out at the engines and then do a idle to wot test and record what happens.

 

[Racingfrank7]

Thanks Frank, I understand where you're coming from but when you're at the helm you can "feel" that there is a problem and that it's not just a cable length or rev counter calibration issue. You can "feel" the port engine struggle.
Cheers
David

So are you saying you can feel a misfire ?

 

[DavidJ]

So are you saying you can feel a misfire ?

I and everyone could easily feel or sense a misfire but that's not the problem.
What I'm trying to explain is that at the helm and after numerous trials you have more information than I can show on the video.
I could of course be wrong but the stuck turbo and/or leaking compressor seem to fit my helm experience.
Unfortunately I'm not on the boat again until September so I can't try out any of the advice until then.
Thanks to all, I'll feed back in Sept
Cheers
David

 

[DavidJ]

Thanks for all the replies in July and I'm on my way back from the boat having tried all the suggestions.
Firstly the turbo spins beautifully so not seized but of course I could have tip wear but I've only done 400 hrs from new. No black smoke by the way.
I did the bubble test and had some bubbles from the compressor bolts (in fact both compressors). A small tighten up and that was cured but made no difference to the problem.
Both throttle lever cables bottom out on the engines and have the same position on the helm.
I did A_8 suggestion of WOT test. Interestingly the port engine reached 3500 while the starboard hit 3650. Speed reached was 28 knots which isn't bad with end of season bottom.and a bit of sea chop. I can reach over the bathe platform and polish my SS props so they were good.
I'm back again in October if anyone has further ideas. I'd like to fix up a pressure test for the turbos ...Any suggestions how to do this without spending a fortune or is it time to bring in a local Spanish Volvo guy.
Thanks again for all your past suggestions
Cheers
David

 

[jimmy_the_builder]

Thanks for all the replies in July and I'm on my way back from the boat having tried all the suggestions.
Firstly the turbo spins beautifully so not seized but of course I could have tip wear but I've only done 400 hrs from new. No black smoke by the way.
I did the bubble test and had some bubbles from the compressor bolts (in fact both compressors). A small tighten up and that was cured but made no difference to the problem.
Both throttle lever cables bottom out on the engines and have the same position on the helm.
I did A_8 suggestion of WOT test. Interestingly the port engine reached 3500 while the starboard hit 3650. Speed reached was 28 knots which isn't bad with end of season bottom.and a bit of sea chop. I can reach over the bathe platform and polish my SS props so they were good.
I'm back again in October if anyone has further ideas. I'd like to fix up a pressure test for the turbos ...Any suggestions how to do this without spending a fortune or is it time to bring in a local Spanish Volvo guy.
Thanks again for all your past suggestions
Cheers
David

Mildly bushed stbd prop? Swap the props over and test again to (dis)prove.

 

[aquatom]

Defiantly looks like worn turbo symptoms.

The hours run don't make much difference to turbo wear. All the KAD engines suffer from this at some point but it is mainly on boats with outdrives where the seawater level in the exhaust is only approx 20cm below the turbo. We very rarely have to replace turbos on KAD engines connected to shafts.

From experience all you need to do is to inspect the gap between the blade tips and the housing on the exhaust side of the turbo.

Fit a pair of turbos or you will be complaining that the other engine is lagging behind afterwards!

I can't see that this is anything to do with exhaust temperatures burning the tips of the blades as the housing is normally worn away more than the blades.

 

[DavidJ]

Thanks Jimmy and Tom
I'll swop the props over when the boat is out in the spring. I dare not hang over the side and do it.
The inlet side blades were easy to look at. Grateful for any advise on how to reveal the exhaust side blades. Very useful pics and interesting wear profile on the blade tip.
Cheers
David

 

[Portofino]

You take the exhaust elbow off -LHS -easily done .

if it looks like this replace for new £ from 165 for after mkt

Vanes have worn tips reducing boast pressure

As mentioned earlier there's issues around the SWCAC - if it a bit fouled then the inlet air temp is higher than norm , runs leaner and EGT increases along with usual end /mid season hull fouling = extra strain to plane -burnt tips are culmulative -comes on slow .

 

[DavidJ]

Thanks portofino, what a great reply.
SWCAC has got me. I've been trying to work it out now for 10 mins. Sorry but EGT also
Cheers
David

 

[Portofino]

Thanks portofino, what a great reply.
SWCAC has got me. I've been trying to work it out now for 10 mins. Sorry but EGT also
Cheers
David

Sorry - Sea Water Charge Air Cooler
- Exhaust Gas Temperature .

Out drive boats tend to be planers like my old S/skr Portofino , Targa 34 ,s Sealine,s xyz etc
So they run the kad300 @3200 or more .Prob is if the power /weight ratio is on near the" edge " -then as natural ageing ,
Weight gian ( cruising stores) -mid -late season fouling both hull and esp props. Then it's tempting to "push the taps "
Got to ask /understand why it's happened -slowly over a few seasons until the symptoms you have .
I had it too .My turbos lasted 9 y 700+ hrs .To be fair I had Vp agents clean the cooling system @y 5 ,which I guess help keep inlet temps down ?
Also never really exceeded 3200 -3 to 3100 or nearer 3000 being the norm to cruise.
I do not think the same boats with D6 ,s had the same prob as much better torque and power to cope so not running near or exceeding the load to shoot up EGT,s - but you swap kad300 turbo issues for DPH external steering ram issues .

With the Kad300 great engine if not overloaded (-theres the prob )and you have to be right on top of the "by the book " maintenance .
Otherwise end up chasing your tail round in circles .

 

[A_8]

It's a very good suggestion to swap the props to disprove its them, as long as you can reach the inner prop it should not be a problem swapping them while in the water. I've done it having had the same issue as you and it turned out to be the props. You could also find a sheltered beach and pull the boat in so that you can stand in the water swapping them, I've done that too but make sure you are on the right side of any tide.
My turbos looked like the worn ones in the pictures after 13 yrs but they were equally worn on each engine and only put me down about 50rpm at WOT on both engines. You may need or want to change them anyways but from the video the engine is lagging from low rpm's before the turbo is in play so it's more likely something else.

After I put new props on max rpm's was identical at 3850 and the boat gained 2 knots top speed.

 

[aquatom]

You take the exhaust elbow off -LHS -easily done .

if it looks like this replace for new £ from 165 for after mkt

Vanes have worn tips reducing boast pressure

As mentioned earlier there's issues around the SWCAC - if it a bit fouled then the inlet air temp is higher than norm , runs leaner and EGT increases along with usual end /mid season hull fouling = extra strain to plane -burnt tips are culmulative -comes on slow .

I'm not sure what I'm missing here.

Blocked charge air cooler causes less efficient cooling of air. Warmer air is less dense. Kad 43 are mechanical fuel pumps and can't allow for different air temperatures, so inject a preset quantity of fuel.
Less dense air and the same amount of fuel make a rich mixture.

 

[DavidJ]

Thanks portofino, A_8, and Tom
Firstly is the SWCAC the same as an aftercooler if not do I have one on my Kad43.
My Sealine S37 with Kad43's and a decade worth of clutter will be pushing the limits of the compressor and turbo so any weakness will show.
It's difficult to say how long I've has the problem because I've been through a number of issues with speed modules failing, clutches failing and slack belts (which took me far too long to diagnose!) which have all effected my running up performance.
In October when next out in Spain I will back upto a beach (the swimmers safety buoys have usually been taken down by then) and swop the drives........interesting one that!!
Incidentally I've ordered a laser tachometer from eBay and will check the rpm against the dial reading.

I return to an earlier question of the possibility of measuring turbo pressure without spending too much.
Thanks all thus far
Cheers
David