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post #99 of Old 10-16-2007
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Black Max prop performance on a 5500-6000 lb Flicka 20

This is from Pete, a 1979 Flicka 20 owner, about using the Mercury Black Max aka Elephant Ears prop on his 6HP Tohatsu 25" shaft outboard.

I have a 1986 Flicka with the Nissan 25" 6HP and will be getting either this prop or the one discussed by TohatsuGuru.


I have been using the prop on my Tohatsu 6hp 25in shaft motor for the
past two months and am very impressed with its performance. For the
sake of comparison, I used the stock prop a couple of times , then
sacked it in favor of the black max. The motor is new so I followed
the break in recommendation not to operate at more than 3/4 throttle
for the first ten hours. At just under 3/4 throttle, at slack tide
against a light head wind, the prop pushed my Flicka out of the
harbor at 4.8 knots over the ground, or so said my GPS. The break-in
allows a couple of short full throttle bursts, and during these I hit
5.4 and 5.3 knots, which I believe is pretty close to hull speed on a
Flicka. I don't have a tach so I can't report on the rpm, but based
on these results I think it safe to say that the prop should push the
boat at about 5 knots at 3/4 throttle in calm water. As might be
expected, there is slightly more vibration with the black max than
with the stock prop, but I didn't find it excessive. I find the 6 to
be pretty noisy at full throttle, but I don't think that is a
function of the prop. The biggest difference is in backing. Throw the
standard prop into reverse and not much happens. The boat just keeps
on going forward, slowing down very gradually. The Black Max however
really functions as a brake when I approach my mooring, and seems
almost as effective as reverse on my previous boat, which had a 30hp
Yanmar. When I threw the Yanmar with its 3-blade into reverse you
could hear and feel it "bite" into the water. You get a similar
sensation with the black max, but nothing even close with the
standard prop.
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