Re: Volvo/Autoprop not making rated RPM..advice please


amelliahona <no_reply@...>
 

Hi Niels:

There are a host of reasons why the engine may not make RPM:

1. RESTRICTION IN THE FUEL SUPPLY;
a. Check that the fuel supply valve is completely open, I couldn't make
RPM once and found that an object had fallen against the fuel shut off valve
in the quaterberth companionway and had partially closed it.
b. Partially clogged fuel filter(s), either or both of the on engine fuel
filter or the in line fuel filter.
c. Bad lift pump (more difficult to diagnose)
d. Clogged injectors (diagnose by swapping for new injectors, since it
is wise to have a spare set aboard, expensive though)

2. RESTRICTION IN THE AIR SUPPLY:
a. Turbo blades not turning easily due to:
a1. Coking in the turbine housing or on the turbine blades as discussed
by others.
b1. Coking of lubricating oil in the turbo center housing due to not letting
the turbo cool properly prior to shut down. Either item can cause the turbo to not
spin normally. Remove the exhaust side or the induction air side (whichever is
easiest, reach in and spin the turbo blades by hand. They should spin freely. If not
trouble shoot the cause.
b. Clogged or collapsed air filter.

3. EXCESSIVE LOADING OF THE ENGINE:
a. Dirty Prop (you already verified this isn't the problem).
b. Transmission malfunctioning (I haven't a clue how to trouble shoot this).
c. Dragging shaft brake. (rule out by direct observation).
d. Incorrect prop or prop malfunction. Can you make better RPM in reverse?

Be methodical in trouble shooting. Verify each component and good luck.

Gary Silver, Amel SM 335 with a Yanmar engine.

--- In amelyachtowners@yahoogroups.com, "Niels Faerch" <nrfaerch@...> wrote:

We're only getting 2400RPM with wide open throttle. The prop is clean
as is the underbody. This means we are only capable of developing
around +/- 60% of rated power say around 50-ish HP.

Is is everyone accepting this or are you getting your props re-pitched
prop?

Would I be better off changing to a regular adjustable pitch
feathering prop?

Thanks

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