Propeller pitch

[fushion julz]

I've done that already, Paul (and it looks clean)...but the lift pump appears to be the original one and, if the diaphragm is in any way worn, it may be pumping at reduced pressure and volume. Given how cheap it was to purchase a brand new one, I thought it was worth a shot.
It has to be the easiest thing to change that could (potentially) have a big effect.

I was considering ditching the mechanical one altogether and replacing with an electric one, but am going to give this a try for now...it was obviously good enough for a standard engine in the past, so see no reason why one in good condition wouldn't be good enough now.

[Richard]

Lo Julz,
Doe's your rocker cover breather still blow oily fumes into your turbocharger air intake. If so have you ever removed
the impellor casing and washed the oily sludge off the impellor blades ,the backplate and the inside of the casing.
If you haven't then I would do that and also clean out the air cooler tubestack which will be restricting air flow.
We used to do that if the Boost pressure gauge didn't show around 12 psi at max RPM 2,400 on even fairly new Perkins,
the boost would drop to around 8 psi and the boats top speed would be well down.
Also when Perkins supplied our first 180 HP units they came with a cube shaped air cooler that was 12"x12"x16" ,
do you still have the tubular unit mounted above the gearbox below the turbo.I think Alan Burnard had to mount his
bigger intercoolers on the rear deck with longer hoses when he replaced his 145 HP units.
Regards
Richie.

[fushion julz]

Thanks for that reply, Richard.

Ok...so there is, obviously, a little mist from the crankcase breather...However, it isn't a lot, mostly disappears after a while and I've taken the intake off and inspected the impeller blades for wear and there is no oily residue at all...the blades are a little discoloured (black), but it appears to be sooty rather than oily. The turbo is a Garrett marked A/R 60 and is about 550hrs old.

I've had the charge cooler off recently and have cleaned out the stack pipes...However, they were pretty clean and not restricting flow at all. The charge cooler is the standard Bowman cylindrical type on top of the gearbox oil cooler.

I don't have a boost gauge fitted, but suspect that at <2000rpm the boost pressure is going to be negligible in any case. A boost gauge (along with a fuel pressure gauge) is on the list of things to do to to try to troubleshoot the issue.

I have now received a new fuel lift pump (a straight mechanical replacement) so will be trying that very soon.

[Paul Fl]

Hi Julz, I have just checked the Perkins-Sabre Installation Manual Page 33 and they recommend an OD of 5/16" (close to 8mm) for the FEED pipework for engines up to 200HP which will use 9+ galls per hour. For 240HP and above the next step is 10.00 mm OD

It seems odd to specify OD rather than ID, but I did not write the manual.

If you text me your e mail I will send you an Installation Manual PDF.