"NOYB" wrote in message ...
"Matt Lang" wrote in message
om...
(Jon.boston) wrote in message
. com...
I have 23' 2000 Outrage, 225 Merc Optimax. The boat will go 29 Knots
@ 5000RPM. Is this about what I should expect for a speed or will a
different prop pitch make this higher (without suffering at the low
end too much).
What effect does twin engines have for top speed?
Thanks,
Jon
WOT for this motor is 5750 RPM ... top speed wise you may be able to
go down 1 or 2 pitches and go faster. You would lose low end
acceleration ... its always a trade off.
Actually, it's just the opposite. If you drop pitch, you *gain* low end
acceleration. The only reason that you might go faster with a lower pitch
prop is that the lower pitch prop will allow the engine to turn at the
higher RPM
You probably get better fuel
economy with the prop you have right now...
Maybe. He may have a lot more prop slip with the current prop.
Maybe having 2 props may work for you .. one high and one low pitch
... put on the prop that fits your needs for the day and bring the
other as a spare.
You should put on the prop that allows the engine to turn at the recommended
maximum WOT operating RPM range.
remember too weight is a factor. typically when i prop a boat its
fairly unloaded, 1/4 tank of gas, not much gear, 1 or 2 people. i
usually try and aim a little higher then wot. all modern engines have
max rpm protection and will usually set a code if this is achieved
simply as a record.
other things to think about. its a 4 year old optimax. how many hours?
ive seen quite a few cracked reed problems with opti's, this will rob
power. the opti's are a very sophisticated engine with quite the
complex fuel delivery system.
my adice, take it too your local professional merc dealer.