Kad 42s power loss

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Keithleask

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Hi again guys, well, same problem with the lack of power.! Changed all pre fuel filters , 2 on each engine and the engine fuel filter on each engine, took her out this afternoon and the superchargers come in ok went up to 3400 revs , just under 28 knots but the turbos never came in at all. Had the throttles full on gradually but once I eased them back a bit it seemed to help with revs / power but as soon as I throttled up again felt like a hesitation and def no turbo pick up, any ideas much appreciated, thanks
 
We had KAD42's on the last boat and suffered power loss on one engine. Spent ages going through everything before someone pointed me in the direction of the props on the other side. Turned out the props were spinning on the hubs....they are rubber bushes/sleeves that rely on tightness of fit/friction to hold the prop on the hub and they had given up the ghost. Symptoms were one engine (the one with knackered props) running to predicted revs and the other struggling.

Symptoms on your boat don't sound the same but may be worth having a look just in case something is going on there. Your revs don't sound too far out but I guess you should be making more than 28 knots?? Maybe something in the drive train i.e. props
 
Greg2 said:
We had KAD42's on the last boat and suffered power loss on one engine. Spent ages going through everything before someone pointed me in the direction of the props on the other side. Turned out the props were spinning on the hubs....they are rubber bushes/sleeves that rely on tightness of fit/friction to hold the prop on the hub and they had given up the ghost. Symptoms were one engine (the one with knackered props) running to predicted revs and the other struggling.

Symptoms on your boat don't sound the same but may be worth having a look just in case something is going on there. Your revs don't sound too far out but I guess you should be making more than 28 knots?? Maybe something in the drive train i.e. props
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Two points here.

1 , if the prop bushes were slipping the revs would be at max as the engines are not loaded due to the prop spinning on the hub.

2. At 3400 rpm the turbos are def working as the supercharger cuts out around 2800 rpm, lift the engine hatch next time you do a test you will see the front of the charger pulley stationary, the belt still turns when the engine is running.

I'd say your turbos are worn, take the exhaust elbows of and look at the turbine blade, if there is a gap around the outer edge its worn, by the age of your boat I'd say its highly likely.
 
volvopaul said:
I'd say your turbos are worn, take the exhaust elbows of and look at the turbine blade, if there is a gap around the outer edge its worn, by the age of your boat I'd say its highly likely.
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+1
Symtoms very much like I experienced a few years ago. I fitted boost guages and watched the pressure drop from a 20 psi to 7 psi as soon as the revs hit about 2800 when the supercharger cut out.

The gap between the turbine blades and the housing was about 2mm - it should be 0.42mm max!. Cost £2000 to bring the smile back:(
 
Hi Pendana,

It is on my winter checklist to check my turbo's as I am low on revs. Out of interest what was the effect of the new turbo's? Do you gain many revs?
 
rlw said:
Hi Pendana,

It is on my winter checklist to check my turbo's as I am low on revs. Out of interest what was the effect of the new turbo's? Do you gain many revs?
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I did my port engine KAD44, had the turbo rebuilt. Engine went from limp lifeless weak piece of carp to a fire breathing monster :cool:
 
Hmm sounds tempting :)

Did you have the turbo's refurbished or buy new volvo ones. I have not looked into pricing yet but it seems they can be refurbished by a turbo specialist as they are garreth? tubo's. Volvopaul I'd be interested in your take on this?

Rob
 
rlw said:
Hmm sounds tempting :)

Did you have the turbo's refurbished or buy new volvo ones. I have not looked into pricing yet but it seems they can be refurbished by a turbo specialist as they are garreth? tubo's. Volvopaul I'd be interested in your take on this?

Rob
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They can be refurbished, I've just had two done and they look like new but you have to paint them green again which is no real hardship. VP can organise all this, he removed and refitted mine.
 
rlw said:
Hmm sounds tempting :)

Did you have the turbo's refurbished or buy new volvo ones. I have not looked into pricing yet but it seems they can be refurbished by a turbo specialist as they are garreth? tubo's. Volvopaul I'd be interested in your take on this?

Rob
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Yes it worked, as stated just done one for crazy 4557.
 
It would be VP if he lived closer :)
Although you have me thinking maybe strategically planned uk customer visit is in order :)
 
Kad 42,s

volvopaul said:
Two points here.

1 , if the prop bushes were slipping the revs would be at max as the engines are not loaded due to the prop spinning on the hub.

2. At 3400 rpm the turbos are def working as the supercharger cuts out around 2800 rpm, lift the engine hatch next time you do a test you will see the front of the charger pulley stationary, the belt still turns when the engine is running.

I'd say your turbos are worn, take the exhaust elbows of and look at the turbine blade, if there is a gap around the outer edge its worn, by the age of your boat I'd say its highly likely.
Click to expand...

Guys thanks for the observations, this is quite odd how they were fine several weeks ago, all worked fine the superchargers ran up then the turbos cut in and a lot of power, have not been doing ANY flat out , or even in the 15-20 knot range as only been poodling about the Medway and doing stuff on the boat. If it were purely down to turbo wear then I do not think they would have been running so well several weeks ago and not had any load on them since?
 
Greg thanks for the input, I would be surprised if it is wear on the turbos that has made such a difference in several weeks when I have only been doing river speed limit and not pushing the boat at all. Can see that because of the age of the boat there probably is wear on them , do not know if they have ever been replaced? But to drop off that quick in a few weeks with very little use is a surprise !
 
Paul, if it is the turbos what is likely expense, new or refurbed ones , is it a mission to remove. / re fit them, actually served my apprenticeship on steam power station turbines , a little bigger than these ones though!!
 
Keithleask said:
Paul, if it is the turbos what is likely expense, new or refurbed ones , is it a mission to remove. / re fit them, actually served my apprenticeship on steam power station turbines , a little bigger than these ones though!!
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It depends what boat you have as to access to each engine.
 
Paul, yes of course sorry should have said. It's a sunseeker Martinique 39 , access is not that bad , I think, bit awkward because you are at the back of the engines leaning over but am small enough to be able to lie over the tops and work away, but if you think it is too much and tricky then fine,
 
Keithleask said:
Paul, yes of course sorry should have said. It's a sunseeker Martinique 39 , access is not that bad , I think, bit awkward because you are at the back of the engines leaning over but am small enough to be able to lie over the tops and work away, but if you think it is too much and tricky then fine,
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Not a problem to remove the starboard one, the port might be a bit tighter getting at the oil feed and return pipes.
 
Ok that being the case and it is definitely the turbos what do you think a re build would come in at a rough guess?, if you would rather not put it on here, understand perfectly, thanks
 
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