Volvo KAD32 acceleration problem

[picardy]

I have a KAD32 (2002 year) with 215 hours. It was worked fine until today. Although it runs OK on tickover (and sounds right) as I moved the gear lever forward there was no usual increase in power. However if I moved if far enough suddently the engine jumped to 2,500 revs or so. ie it was either up to 1,500rpm or over 2,500 rpm but nothign in between.

I have read about other experiences with clutch problems on the kompresser on this forum . Engine oil, belts etc changed this spring. Fuel filters and fuel are last years - i was going to change filters when last years fuel was used up.

In netural the engine increased through the rev range without any problem and the compresser cut in and out as usual. It just seems to be a problem when under load.

Any suggestions on where to start would be greatfully received.

 

[Nautorius]

Hello!

I would guess your belts may be slipping....... or it has some manky fuel in her. Last year my boat (single Kad 32) had lain idle for 8 months with 3/4s of a tank of Diesel. When I powered her up I had the same issue. Was some diesel bug!. Loaded her with Soltron, ran her gently for 30 mins, topped up with new fuel and powered her up. Same thing happened first time, second got better. After a full tank with Soltron no probs.

Try some additive and then keep checking your filters,

Cheers

Paul /forums/images/graemlins/smile.gif

 

[andyball]

The springy flap thing inside the air filter box can stick slightly open.

also the air hose after the box is known to split ime - usu obvious on close inspection.

 

[amf]

Clean prop and bottom?

Used to happen to us in our old boat if prop or hull dirty. Always experienced some rev gap between compressor on/off on our KAD32 but this got wider if engine having to work harder (ie. throttle further forward) before the compressor kick-in revs (1500 rpm?).

 

[Peanuts]

A very interesting problem. Have no info on your boat apart from having a KAD 32, is it a single or twin? Regarding the problem,apart from changing the belts and other items you mention have you had any other work done or any other problems that might be related? I agree with the reply about the slipping compressor belt, it could be worth removing,inspecting the belt and pullies then refitting with the correct torque figures. You mention that in neutral when you open the throttle it accels normally with the compressor cutting in and out at the correct RPM's. When you open up under load are you moving the throttle quickly to fully open or just say 3/4 open? Is there any way you can try the engine under load with the engine compartment open so you could view the compressor to see if it operates. Have you tried (under load) to accelerate slowly to see if the compressor cuts in and out.
I know this seems to be question after question but I am attempting to pin-point the possible problem.
I look forward to your reply.

 

[picardy]

Thanks for all your comments. It is a single installation on a Sealine S23. The belts have just been changed by a Volvo Dealer using a torque wrench and they do feel pretty tight.

No other work (other than routine servicing) has been done and the engine worked fine a week before on the same fuel. The sea was pretty lumpy on Saturday - could it be that some cr*p in the tank was sucked through and that it is only a temporary problem or am I dreaming if I think it will resolve itself!

I do increase power slowly. I have not tried increasing power while watching to see if the compresser cuts in so will do that. I will also add some fuel treatment although the tanks were left 90% full over the winter with a fuel treatment in.

Can anyone tell me where to get diesel fuel tested to see if the tanks need to be pumped out and cleaned?

Your help so far is much appreciated.

 

[duncan]

excuse my ignorance but I had though the 32 had a supercharger and a turbo........your symptoms would match a failure of the supercharger (in some way) perfectly.

of course if it doesn't have one that no use to you at all............

 

[Peanuts]

It is interesting to note that you state the engine was working fine a week before you had the servicing done.
I don't think it's the fuel (at the moment) but what is interesting is that the speed/RPM you quote in your original post are approx the cut in/out RPM's for the compressor. I didn't want to mention this in my first reply as I wanted all the facts.
When the engine was serviced were you present and exactly what was done, did any one delve inside the electrical box on top of the engine.
The reason I ask about how you opened up was if you go full throttle it brings a 'kick down' switch into operation but as you don't it eliminates that.
Have you had any type of water leaks over the engine, eg sea water pump.
Once again lots of questions, look forward to your reply and by the way where are you based - the boat that is.

 

[picardy]

I was present when the engine was serviced and no-one touched the electrical box on top of the engine. I am interetsed by the comments about compresser failure but it does cut in and out normally when revs are increased in neutral.

There are no visible water leaks. The boat is kept in Plymouth and as we have 2 young children - boating is no fun with an unreliable engine - I have decided to pay for 1 hour of a Volvo Dealer to come and diagnoise the problem at sea in Plymouth this Friday. He feels from the symptoms that it may be a belt problem do you agree with that?

I will let you know the results (and cost!!) of his visit.

 

[duncan]

from your earlier description of the power (under load) coming in at around 1500rpm - this will be the turbo coming in. The supercharger (compressor) is mechanically driven (maybe belt) and delivers you additional power (not revs) from the start. Thus you get a much smoother transition of power through the range and, importantly, do not have prop issues associated with a lack of power below 1500 that might make it impossible to prop smaller craft as highly as they needed at the top end...............

If the compressor is belt driven (likely) then unless the belt is actually missing you would hear it and see it slipping on the compressor pulley.

If the compressor has it's own wategate and/or other bypass (for when the turbo kicks in) then it's also possible this is jammed open/faulty.

Make sense?

 

[Peanuts]

If the compressor cuts in and out when you open the throttle when you are neutral then I don't consider there to be a major problem, apart from the belt playing up eg slipping i just don't understand whats happening.I did have a case the other day when the belt looked OK but when I inspected the belt nearly all of the ribbed part was missing, just like losing the tread off a remound. I am not saying thats what you have it's just an example.
Please let us all know the outcome of your visit from the VP engineer.

 

[[2068]]

[ QUOTE ]
from your earlier description of the power (under load) coming in at around 1500rpm - this will be the turbo coming in. The supercharger (compressor) is mechanically driven (maybe belt) and delivers you additional power (not revs) from the start.]

[/ QUOTE ]
No is doesn't: there is a clutch that engages the supercharger at 1500rpm and disengages it at 2500rpm. The turbo doesn't really come on song until well above 2200rpm, where it is providing the bulk of the air boost.

[ QUOTE ]

Thus you get a much smoother transition of power through the range and, importantly, do not have prop issues associated with a lack of power below 1500 that might make it impossible to prop smaller craft as highly as they needed at the top end...............


[/ QUOTE ]
Sorry, but this is just rubbish. Neither the turbo nor the supercharger are doing anything useful below 1500rpm. Possible causes of not being able to hit the clutch engagement point are hull fouling, fouled or damaged props, overpropping, fuelling issues or fuel pump problems: basically anything that could "overload" the engine just enough to stop it from smoothly reaching the supercharger clutch engagement point.

[ QUOTE ]

If the compressor is belt driven (likely) then unless the belt is actually missing you would hear it and see it slipping on the compressor pulley.

If the compressor has it's own wategate and/or other bypass (for when the turbo kicks in) then it's also possible this is jammed open/faulty.


[/ QUOTE ]
Agree that checking belts is worthwhile, but he says they're tight. There is no compressor wastegate. It relies on the clutch disengaging at 2500rpm.

[ QUOTE ]

Make sense?


[/ QUOTE ]
Not really /forums/images/graemlins/smile.gif

dv.

 

[aydur]

I was present when the engine was serviced and no-one touched the electrical box on top of the engine. I am interetsed by the comments about compresser failure but it does cut in and out normally when revs are increased in neutral.

There are no visible water leaks. The boat is kept in Plymouth and as we have 2 young children - boating is no fun with an unreliable engine - I have decided to pay for 1 hour of a Volvo Dealer to come and diagnoise the problem at sea in Plymouth this Friday. He feels from the symptoms that it may be a belt problem do you agree with that?

I will let you know the results (and cost!!) of his visit.

Hi, I am currently having this issue with my KAD32 in my 7 Metre Ribtec.

Did you ever resolve your issue or could you shed any more light on it for me?
Kind Regards,
M