I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine one,
for those who followed my earlier travails!) which should give it about 230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took it out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water on
skis. Top speed is pretty good (nearly 40 mph, and this is at an elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner trashed
the prop on a sand bar. Before he sold it, he purchased a new four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks about
the same as the previous 17-pitch prop, which he left in the boat). My
suspicion is that this prop is just too much for my engine to turn, but I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is adjusted
correctly), the engine peaks out at 3500 rpm. According to a Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn

At 5000ft I would be surprised if you have more than about 175-180 horses.
MY guess to get the RPM where it should be figure on buying a 15p prop. I
would think your RPM range should be 4200-4600.


"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat). My
suspicion is that this prop is just too much for my engine to turn, but I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn

I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat). My
suspicion is that this prop is just too much for my engine to turn, but I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn

In article ,
says...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat). My
suspicion is that this prop is just too much for my engine to turn, but I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn


Ok, I'm new here and it's been a long time since I had anything to do
with small boats and even then the prop wasn't my concern. Now it will
be, Why will a four bladed prop slow you down?

Thanks.
--
MikeG
Heirloom Woods
www.heirloom-woods.net

A 4 blade prop of the same pitch will be slower on top end due to the extra
blade surface (althought a 4 blade will usually be smaller in diameter to
help compensate - it still will be slower on top end).
A 4 blade prop of the same pitch will be faster out of the hole due to less
slippage. A 4 blade is more efficient at lower rpms.

If your not comparing same pitch then all bets are off.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"MikeG" wrote in message
ws.com...
In article ,
says...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the
original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it
about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took
it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water
on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat).
My
suspicion is that this prop is just too much for my engine to turn,
but I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a
Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine
be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because
it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather
know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn


Ok, I'm new here and it's been a long time since I had anything to do
with small boats and even then the prop wasn't my concern. Now it will
be, Why will a four bladed prop slow you down?

Thanks.
--
MikeG
Heirloom Woods
www.heirloom-woods.net

In article xcgQc.246823$XM6.7643@attbi_s53, says...
A 4 blade prop of the same pitch will be slower on top end due to the extra
blade surface (althought a 4 blade will usually be smaller in diameter to
help compensate - it still will be slower on top end).
A 4 blade prop of the same pitch will be faster out of the hole due to less
slippage. A 4 blade is more efficient at lower rpms.

If your not comparing same pitch then all bets are off.




Ok then, if I understand this properly, if my main interest is strictly
fishing and towing a joy rider is only the faintest of possibilities and
assuming the same pith I'd be better served by a three bladed prop since
good hole shots are not a necessity but getting from one spot to another
in the fastest most efficient way would be?

Thanks again for the info.
--
MikeG
Heirloom Woods
www.heirloom-woods.net

You are correct Mike. For max top end speed you want to prop with a good
performance SS prop at about 300 rpms below max rated. This will give you
the best top speed but will hurt your hole shot some.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"MikeG" wrote in message
ews.com...
In article xcgQc.246823$XM6.7643@attbi_s53, says...
A 4 blade prop of the same pitch will be slower on top end due to the
extra
blade surface (althought a 4 blade will usually be smaller in diameter
to
help compensate - it still will be slower on top end).
A 4 blade prop of the same pitch will be faster out of the hole due to
less
slippage. A 4 blade is more efficient at lower rpms.

If your not comparing same pitch then all bets are off.




Ok then, if I understand this properly, if my main interest is strictly
fishing and towing a joy rider is only the faintest of possibilities and
assuming the same pith I'd be better served by a three bladed prop since
good hole shots are not a necessity but getting from one spot to another
in the fastest most efficient way would be?

Thanks again for the info.
--
MikeG
Heirloom Woods
www.heirloom-woods.net

That must be a pretty heavy boat. Try going back to the 17. You might even
want to try a 15. Personally I prefer to run the wot rpm a little high to
improve the hole shot. After all you can control how long you run it wide
open. I let my 5.7 turn about 5200 but seldom keep it there for more that 4
or 5 minutes.

"Joseph Stachyra" wrote in message
...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the
original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water
on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat). My
suspicion is that this prop is just too much for my engine to turn, but
I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine
be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because
it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather
know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn

Don't know what boat you have James but Turning a 5.7 at 5200 rpms for 4 or
5 minutes at a time will destroy the engine. Don't expect it to last more
than a couple of seasons if that long.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"JamesgangNC" wrote in message
k.net...
That must be a pretty heavy boat. Try going back to the 17. You might
even
want to try a 15. Personally I prefer to run the wot rpm a little high to
improve the hole shot. After all you can control how long you run it wide
open. I let my 5.7 turn about 5200 but seldom keep it there for more that
4
or 5 minutes.

"Joseph Stachyra" wrote in message
...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the
original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a marine
one,
for those who followed my earlier travails!) which should give it
about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I took
it
out
on the lake last week and while the engine seems to run well, there's
absolutely no way the boat could have gotten an adult out of the water
on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up onto
plane. As you might guess from the subject line, I suspect the prop.

This boat apparently came with, and was pretty much always run with, a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it looks
about
the same as the previous 17-pitch prop, which he left in the boat).
My
suspicion is that this prop is just too much for my engine to turn,
but
I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a
Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this engine
be
able to handle a 19 pitch? Actually, I'll buy a prop anyway, because
it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather
know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn

Depends on the engine :-) Late model 1 ton truck block, 4 bolt main, chevy
pink rods, keith black pistons, crane roller cam and roller rockers,
edlebrock performer rpm aluminum heads and aluminum intake.

"Tony Thomas" wrote in message
news:muhQc.90170$eM2.58740@attbi_s51...
Don't know what boat you have James but Turning a 5.7 at 5200 rpms for 4
or
5 minutes at a time will destroy the engine. Don't expect it to last more
than a couple of seasons if that long.

--
Tony
my boats at http://t.thomas.home.mchsi.com

"JamesgangNC" wrote in message
k.net...
That must be a pretty heavy boat. Try going back to the 17. You might
even
want to try a 15. Personally I prefer to run the wot rpm a little high
to
improve the hole shot. After all you can control how long you run it
wide
open. I let my 5.7 turn about 5200 but seldom keep it there for more
that
4
or 5 minutes.

"Joseph Stachyra" wrote in message
...
I keep telling people, 4 blade props will slow you down, and nobody
listens.....
go back to a 17" three blade, or check with a boat dealer what the
original
prop was....
if you want to push a 4 blade, then go to a 250 hp outboard.

"Shawn Willden" wrote in message
...
I have a 20' Bayliner, a 1990 with a 5.0L Merc and (I think) Alpha 1
outdrive. The engine has been modified with a 4BBL carb (now a
marine
one,
for those who followed my earlier travails!) which should give it
about
230
HP (as comared with 200HP with the original 2BBL).

After getting the engine fixed up with the right kind of carb, I
took
it
out
on the lake last week and while the engine seems to run well,
there's
absolutely no way the boat could have gotten an adult out of the
water
on
skis. Top speed is pretty good (nearly 40 mph, and this is at an
elevation
of over 5000 feet) but the boat is really slow to dig its way up
onto
plane. As you might guess from the subject line, I suspect the
prop.

This boat apparently came with, and was pretty much always run with,
a
three-bladed 17 pitch prop. This spring, however, the former owner
trashed
the prop on a sand bar. Before he sold it, he purchased a new
four-bladed,
19 pitch aluminum prop (don't know what the diameter is, but it
looks
about
the same as the previous 17-pitch prop, which he left in the boat).
My
suspicion is that this prop is just too much for my engine to turn,
but
I
don't really know if 2 inches of pitch make that much difference.

At plane, with a wide-open throttle (assuming the throttle cable is
adjusted
correctly), the engine peaks out at 3500 rpm. According to a
Mercruiser
manual I have, it should run to about 4200 WOT.

So, before I go buy a prop, what do you all think? Should this
engine
be
able to handle a 19 pitch? Actually, I'll buy a prop anyway,
because
it's
cheaper than looking into deeper engine problems, and if it gets me
acceptable performance, I'll stick with it. However, if the current
performance indicates that there might be other problems, I'd rather
know
sooner rather than later, even if I decide not to do anything.

Thanks for any help,

Shawn