Wiggo
regular
Reged: 10/09/2003
Posts: 3280
Loc: (State, Country, etc.)
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Any clues from the panel on this one: I've changed all the filters, but my port lump (KAMD43P) is lazy. When we first get going, it won't rev much over 32-3300rpm at WOT, though the other will pull to 3800. After maybe half an hour, it will begin to rev properly but will never get over 3700 (which is around the red line anyway, I suppose).
I thought of a blocked pickup in the tank, but switching the fuel cocks around to let it draw from the starboard tank makes no difference. There also seems to be a small amount of diesel on the head round the base of the injectors, but everything seems tight.
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The nicest thing about not planning is that failure comes as a complete surprise, and is not preceded by a period of worry and doubt.
Nereid Charter
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Divemaster1
regular
Reged: 15/01/2002
Posts: 1583
Loc: Scotland
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Air supply ??
Turbo, compressor... and or air leak somewhere between them...
One engine low, will hold other one back .... so surprised you get WOT on Stb..
Sure engine is not OK and rev counter (sensor of instrument) is wrong/bad connection (humidity perhaps) ??
You getting expected cruise and top speed?
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Regards, Alf
"The only time you have too much fuel is when you're on fire."
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No_Regrets
regular
Reged: 09/07/2007
Posts: 1210
Loc: Welwyn Garden City, Herts UK.
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Tight valve clearance on the exhaust side perhaps?
That could give those symptoms...when the engine warms up all the way, it works better, but cold it's a dog...
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Birchwood Owners Association (BOA) forum now open here -> http://birchwoodboats.aceboard.com/
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Wiggo
regular
Reged: 10/09/2003
Posts: 3280
Loc: (State, Country, etc.)
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Thanks, I'll look into the valve clearances. Before she's warm, she's a few knots down.
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The nicest thing about not planning is that failure comes as a complete surprise, and is not preceded by a period of worry and doubt.
Nereid Charter
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jezbanks
regular
Reged: 04/04/2005
Posts: 7107
Loc: ality Unknown
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KAMD/KAD 43 is only rated to 3700rpm anyway. If you are running one at 3800 then you are over revving it - though I suspect it isnt and your tachos are not correct.
Have you tried swapping the tachos over? You might find the port one is a bit sticky. How does the boat accellerate? Will it spin up to full revs in neutral, or do you get the same symptoms?
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Wiggo
regular
Reged: 10/09/2003
Posts: 3280
Loc: (State, Country, etc.)
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Hi Jez, you're right about the tachos being inaccurate, so I accept 3700 and 3800 are close enough for jazz.
To be honest, I wouldn't want to let it hit the redline in neutral, so I can't comment on that, but it revs freely enough and will accelerate fine until the port lump runs out of steam. The tachos downstairs show the same problem, so the engine is definitely underperforming. That was what made me initially think fuel starvation and hence change the filters. I'll also change the air filters for the fun of it.
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The nicest thing about not planning is that failure comes as a complete surprise, and is not preceded by a period of worry and doubt.
Nereid Charter
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DavidJ
regular
Reged: 15/06/2001
Posts: 2361
Loc: home Brum, boat Costa Brava
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How about the Turbo?
At 3100 rpm (or so) the compressor has done it's job and switches out leaving the turbo to carry on. Just maybe the turbo isn't whirling around.
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www.jensenworld.co.uk
Edited by DavidJ (13/05/2008 11:04)
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sarabande
regular
Reged: 06/05/2005
Posts: 5169
Loc: Thames valley, or up on the mo...
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Any problems with the port gearbox / transmission, or even an out of shape prop ?
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Enlightenment is motor-sailing
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jezbanks
regular
Reged: 04/04/2005
Posts: 7107
Loc: ality Unknown
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certainly sounds like it is down on power. The fact that it gets there eventually just suggests it is being dragged along by the good engine.
Might be worth checking the turbo is spinning freely - do you have any other symptoms such as unburnt fuel out the back?
You coing to the pub tomorrow?
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jezbanks
regular
Reged: 04/04/2005
Posts: 7107
Loc: ality Unknown
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Quote:
How about the Turbo?
At 3100 rpm (or so) the compressor has done it's job and switches out leaving the turbo to carry on. Just maybe the turbo isn't whirling around.
dammit - 3 minutes late...
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