KAMD43 not pulling max revs

[Wiggo]

OK, I am now seriously losing my patience with this engine (port). Injectors all fine, problem fixed with the injection pump, fresh primary filters and air filters, lifted and scrubbed today.

So she's now up to just over 21 knots (from 14 before the bum clean) and I know the props could do with properly sanding or a dose of brick cleaner to get another knot or so.

Starboard engine will pull to 3600rpm, port engine makes 3100 then gradually limps up to maybe 3400 but won't stay there - the revs fluctuate wildly from 3100-3400.

Ideas? Lift pump with a split diaphragm? Crud blocking the pick-up pipe (Col cleared something similar a few years ago with compressed air)?

 

[PaulGooch]

Does it have a secondary filter on the engine ?

 

[volvopaul]

Id say its fuel related, but as cols your man I wont tread on his territory.

 

[DavidJ]

Crud blocking the pick-up pipe (Col cleared something similar a few years ago with compressed air)?

Maybe you have a similar arragement to my Sealine. Just before the primary filters I have an array of fuel taps so I can route to just one tank, can you do this, thus eliminatiing the port pickup.
You could route both engines to the port pickup, the effect should be dramatically bad.

 

[Wiggo]

Can't get hold of Col at the mo, so happy to take anyt advice/offers of help. I did try the fuel taps thing ages ago, but it's woirth a try, I guess. One for the weekend...

 

[KevB]

I had a similar problem with one of my kad43's a couple of years back. My pick up pipes for some reason have a fine wire gauze over them which had become partially blocked.

 

[Wiggo]

I had a similar problem with one of my kad43's a couple of years back. My pick up pipes for some reason have a fine wire gauze over them which had become partially blocked.

That's what I suspect, but I can't figure out how to get the pipes out...

 

[KevB]

If it's a problem to take out the pick up pipes would it be possible to change over the feeds from one pick up to the other and see if the problem moves engine?

 

[Wiggo]

I can switch the feeds to P->P, S->S, Both->Both, P->Both or S->Both but I can't reverse them. I'm not sure if one pickup pipe (starboard tank) on it's own would be enough to feed both engines at WOT, so I might try opening the isolator so they can both draw from both tanks. In that way, the extra draw on the starboard tank should be minimised...

Other than that, does anyone know how much work is involved in replacnig the diaphragm in the lift pump, in case that's the issue?