Joel F. Potter <jfpottercys@...>
What I am about to relate may seem hard to believe but it is absolutely
true. A few years ago I had symptoms exactly identical to yours. I had my
fuel tested, tested flow rates on my Racor filters and had the best diesel
man in town check my engine and fuel system. All was O.K. Believing that
any repair would be a dreadful ordeal, I called Jacques Carteau at Amel. I
enjoy a good relationship with Jacques and he gets great pleasure out of
teasing me. When he told me to clean my propeller I was sure he was joking.
He insisted and told me that the AUTOPROP is particularly sensitive to ANY
GROWTH, even a small amount. Feeling ridiculous and being certain I was the
victim of a joke, I dove on my boat and, believe it or not, there were
several small gooseneck barnacles, most of them on just one of the blades.
I cleaned them off and used sand paper to polish off their "footprint". The
engine problems disappeared immediately.
How can this be? To make a long story short, the AUTOPROP works as well as
it does and is extremely efficient due to the unusual shape of the propeller
blades. The blades, though not interconnected must work in complete
symmetry/unison. If any one blade is more fouled than another, that effects
it's "pitch" or angle of operation. The vortex of water coming off this
blade then causes the other blades to change pitch...it's complicated but I
hope you can understand the relationship.
I hope this will eliminate your problems. Remember, the prop must be
perfectly clean on all three blades. As a proof to this, last week I sold
an 8 month old SUPER MARAMU that sat at a dock here in Fort Lauderdale for
two months. When we pulled the boat out of the water, the propeller was
fouled, but pretty evenly on all three blades. The boat would only go 4
knots at 2000 max R.P.M. and there was a noticeable increase in vibration.
Once clean, all was normal.
Let me know how you solve your problem, please.
Joel F. Potter
SUPER MARAMU #400 "MARY BROWN"