Volvo Penta KAD 42 loss of revs.

How about a slight air leak that gets worse as everything warms right up? Perhaps a pipe joint is just loose and opens more at higher temps. This would tie in with the restart once things have cooled down a bit.
Or maybe the lift pump has a problem that gets worse with heat. You could try swopping them, not easy if they are part of the injection pump.
Engine cutting out at low revs seems to indicate a fuel problem.

Good Luck

David
 
Read this with interest as since you first posted I have developed a similar ish problem on one of our KAD 42's. No problems starting or cutting out but one engine not as responsive as the other and won't achieve the same revs at WOT. Advice I have suggests some diagnostics i.e. turbo boost pressure and fuel flow before tinkering any further.
 
Ditto

Greg2 said:
Read this with interest as since you first posted I have developed a similar ish problem on one of our KAD 42's. No problems starting or cutting out but one engine not as responsive as the other and won't achieve the same revs at WOT. Advice I have suggests some diagnostics i.e. turbo boost pressure and fuel flow before tinkering any further.
Click to expand...

Hi Greg2.
Initially we did not have any starting or cutting out problems. Things have just progressed to that.
Fuel starvation was my initial thought and the thread outlines most of what I have done so far. I have not checked turbo boost as yet,though from tne progression of the problem to difficult starting and cutting out, it has to be either fuel or air supply that have to be the main culprits. That said, I may need to check the turbo pressures if I resolve everything other than the WOT performance.
Will keep you posted.
Cheers
Mike
 
Thanks

DaveSteward said:
How about a slight air leak that gets worse as everything warms right up? Perhaps a pipe joint is just loose and opens more at higher temps. This would tie in with the restart once things have cooled down a bit.
Or maybe the lift pump has a problem that gets worse with heat. You could try swopping them, not easy if they are part of the injection pump.
Engine cutting out at low revs seems to indicate a fuel problem.

Good Luck

David
Click to expand...

Hi David.
Very good points. I'm onto them apart from the fact that the port engine now refuses to start at all.
As I have checked all fuel supply runs up to and including the injector pump it's starting to look like either that or the injectors! I have also checked the air filters and feed pipes which are all OK.
Could be a big ouch coming but I'll keep you posted.
Cheers
Mike
 
I had exactly the same problem a couple of years ago with my KAD43's even down to the revs dropping off the 'bad' engine when turning.

My problem turned out to be..... on the pick up pipes for the fuel mine have a fine wire gauze, why I do not know but presumably to filter some of the bigger crud. Anyway the gauze on the 'bad' engine was partially blocked. A quick clean in some petrol 100% sorted the problem.

Good luck.

Kevin.
 
Thank you.

KevB said:
I had exactly the same problem a couple of years ago with my KAD43's even down to the revs dropping off the 'bad' engine when turning.

My problem turned out to be..... on the pick up pipes for the fuel mine have a fine wire gauze, why I do not know but presumably to filter some of the bigger crud. Anyway the gauze on the 'bad' engine was partially blocked. A quick clean in some petrol 100% sorted the problem.

Good luck.

Kevin.
Click to expand...

Nice one Kevin.
Something I hadn't even considered so well worth a look next time I am on the boat. Did the pick up pipes on your tanks pipes unscrew? I think from memory (which ain't that good)mine are welded in place so could be a bit tricky.
Cheers
Mike
 
Something I hadn't even considered so well worth a look next time I am on the boat. Did the pick up pipes on your tanks pipes unscrew? I think from memory (which ain't that good)mine are welded in place so could be a bit tricky.
Click to expand...

Thankfully it only takes 5 minutes to remove my pick up pipes. I have a plastic fuel tank and they screw in.

One suggestion which I tried temporarily cured the problem. Use the dinghy pump and blow back down the fuel pipe into the tank. This improved things which led me to taking the pick up pipes out and finding the blocked gauze.

Obviously fitting the pump before any of the filters so it's blowing straight back into the tank....
 
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Mike

"It might be in the filters or could of course be debris in the fuel line before the filters."

This is a quote from the first reply (post 2) from me to you back on page 1. I thought you had checked these in a reply later from you? Or had you just checked the filters? You need to start at the very beginning of the fuel supply not just at the filters.
 
Hi Peanuts.
Started at the fuel pickups and have worked back methodically. Even blown back thru the pickups on reverse thrust with an electric dinghy inflator. But haven't checked to see if there is a gauze mesh on the ends of them. Everything has been pulled apart and investigated up to and including the secondary's.
That said those little old lift pumps can appear to be performing by priming the secondary filters, but it is really hard to suss them as they do need to shift a helluva lotta diesel into the system under power, and a sluggish one that is deteriorating could definitely be giving the problems I have experienced.
Any other ideas?
Many thanks
Mike
 
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SovereignDiver said:
Hi Peanuts.
Started at the fuel pickups and have worked back methodically. Even blown back thru the pickups on reverse thrust with an electric dinghy inflator. Everything has been pulled apart and investigated up to and including the secondary's.
That said those little old lift pumps can appear to be performing by priming the secondary filters, but it is really hard to suss them as they do need to shift a helluva lotta diesel into the system under power, and a sluggish one that is deteriorating could definitely be giving the problems I have experienced.
Any other ideas?
Many thanks
Mike
Click to expand...
Let me know if you ever find out...

I've spent a couple of years chasing a similar issue on a KAD43. Crud in the fuel tank pickup: cleared. Blocked filters: cleared. Turbo boost: checked. Lift pumps: swapped. Injection pump: overhauled. Injectors: serviced. Air filters: replaced. Intercooler: cleaned. Fuel lines: removed, cleaned, tightened. B@stard port engine still refuses to pull as well as starboard...
 
Wiggo said:
Let me know if you ever find out...

I've spent a couple of years chasing a similar issue on a KAD43. Crud in the fuel tank pickup: cleared. Blocked filters: cleared. Turbo boost: checked. Lift pumps: swapped. Injection pump: overhauled. Injectors: serviced. Air filters: replaced. Intercooler: cleaned. Fuel lines: removed, cleaned, tightened. B@stard port engine still refuses to pull as well as starboard...
Click to expand...

You have checked the props, haven't you? :D

Could be some damage or even miss matched/wrong size.

How about a dodgy rev counter?
 
b*****D PORT ENGINE!

Just reading this thread as working with greg2 to resolve his issues. But had to respond to the last post. If you have covered and cleared all the things that you lisy in your last post including Turbo Injectors and Injector pumps. Have you checked the valve clearences? As sometimes these can actually close up and when hot allow a slight comustion pressure leak as the valve stop sealing properly, which will manifest its self as a loss of power and revs and the loss of the ability to hold a power setting. Its a long shot but is not covered in this whole post. Also I take it that the injector pump timing and timing gear sets atr spot on and not worn thus throwing the injection timing out?
 
S*%t or bust

Ah well.
I've had considerable time to ponder and my assessment (due to the total refusal to start now and very poor back pressure felt on the lift pump manual primer) that I will be replacing said lift pump when I am back at the boat this weekend.
Well I just feel I have to try somat, and as I think I've covered all the keep it simple stupid (cheaper) options.
I have discussed with a few old hands including John Wanderer and fellow formurite Double Vision. Their assessments also directing me to this area. John said he had resolved a very similar top end performance problem previously through exchange of the lift pump. Paul (Double Vision) also experienced similar lack of top end performance and tracked it down to a "pinhole" in the lift pump diaphragm.
Thanks to Keypart, my shiny new lift pump has arrived and been painted best Volvo Penta green ready for fitting the weekend.
I will of course let you all know how I get on.
Many thanks to all contributers, and just in case, keep any other ideas coming.
Cheers
Mike
 
Not the lift pump!

Well replaced the lift pump and have now started the port engine.
Left it a while and then found it hard to start.
It appears the rail is just not holding pressure.
Haven't taken it out for a full trial under power yet but things don't look good.
Any other ideas Guys or Girls?
Ta
Mike
 
Hi to all:)
I am from norway but will try explain in english:)
I have Skippering several boats from uk and 4 of them with KAD 42s.. targa 38.39.37 and princesses ( i often change boats:D). On those trips back to norway i have had some problems.. 2 times i have had problems with loosing revs on engines on my way.. both times the engines had the same sypthoms as you have.. My problems has been small air leeks in the fuel system causing that the engines often ran vell for 1 hour or 2 before they "cut out". Both times the air leek was on the bleeding screw on the fuel filter.. this leek could not been seen when bleeding the system or running the engines after bleeding.. but when the tempatures in the enginebay and engines where high enough the engines started to suck false air slowly causing low revs and finaly full stop..

Just a tip

Regards
Norwegian:)
 
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