Volvo Penta KAD 42 loss of revs.

Hi and welcome msea

Yes I am M8.

Removing the injectors this weekend to get them all checked out. Just off to a mate's workshop to see if I can mump his injector extractor tool.

Cheers.

PS. You stuck your query on here yet?
 
Peanuts said:
I always stand to be corrected, but if the props were slipping on their rubber bushes would not the rev's be higher not lower? Just like a slipping clutch on a car for example.
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I have experienced a slipping rubber bush on a single prop boat and yes exactly like a slipping clutch and very obvious.......not the problem here.
If you take it out of gear when you have the problem can you rev to 3800?
 
Your problems sound a bit like a more extreme version I had with fuel on TAMD42s.

The underlying cause was the bug blocking a solenoid valve on the port tank. When underway the lift pump could pull through enough fuel but as soon as I stopped the suction on that side pulled the fuel out of the injection system making it very difficult to start. I did not have any power reduction though.

One test I was able to do on my boat was run both engines off the "clean" fuel tank- have you tried this?
 
Thanks for reply Paul,
Mine is slightly different in that respect one engine is off like a good one and the other is 500rpm behind then reaching 3100rpm whilst other is at 3500rpm I think I might have a boost leak from aftercooler but not sure I fancy stood in there trying to feel for leaks !
 
I've a similar problem but a bit weird because my engine (KAD42) temperature got higher before the rev loss.

When engine was cold i.e. just started, it could throttle up to the usual cruising of 3200 rpm. However the temperature did not stay constant and kept on climbing. When the temperature was about to reach boiling point, I reduced the throttle to let the engine cool down. However after the engine was lowered to 2800 rpm, it could not throttle pass 3000 rpm again. Sometimes, it will further drop to 2600 rpm and stayed there.

When the engine was running at 2600-2800 rpm, the temperature would drop accordingly, which means the cooling system should be working fine. And since at the beginning, the engine was able to throttle to 3200 rpm, I suppose this means that the fuel/ injection pumps are working fine too.

The problem started when the temperature got too hot but I had never let the engine temperature reached boiling point. The rev would drop and could not go up again for the rest of the journey.

Anyone has this similar experience?
 
Hi. I have this same broblem on kad42P-A -96 1600h. . After a while cruising rews at 3200 engine starts to slow down loosing power. It has all new filters, turbo gives 1.2bar at 3150, it is new. I just ordered new fuel pump. I hope its it, boat has done this more less occasionally for several years. One time 5 years ago this was tracked to new fuel filter being blocked inside. It was new genuine volvo penta, engine boosted to 2300 and falled its face to 1400. After replacing fuel filter, it was all good. It has 10mm fuel lines with racor filter. If pump makes no diffrens, I bypass racor with straight hoses from tank.
So did you find a fix for this, if so please share your experience.
 
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