Hi All.
We just added a power boat to our fleet (of otherwise sailboats)
1990 Four Winns Horizon 180
Cobra outdrive, 4.3L GM engine

The original owner has two zincs; but I can count 4 (it's in the water right
now) -- QUestion: Does anyone know if there's a zinc behind the prop? Is there
a place where I can just buy a "zinc kit" for the outdrive?

The "factory" prop is a 14.5 x 19 -- that's what's on there now; max RPM is
supposed to be between 4200-4600 and running at 42-45mph

The factory prop is on there now -- it's an ugly thing with non-smooth blades
(they appear welded to the hub) and nicks out of hte blade (ala running thru mud
etc)

I'm getting at optimium trim 4200rpm but only 30mph. Engine is strong with good
even compression.

Would going down in pitch (raising RPM) help any with top speed? We're not
skiers, we just want this for getting to the mainland from time to time.

Oh -- and one thing that really bugs me -- the trim on these boats.... the trim
guage always reads "UP" I suspect the sender is jammed/broken -- but -- should
it allow you to raise it to "trailer mode" while underway? This is the 1st boat
that's allowed me to do that.

Thanks for any advice
-josh


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I'm getting at optimium trim 4200rpm but only 30mph. Engine is strong
with good
even compression.

Would going down in pitch (raising RPM) help any with top speed? We're not
skiers, we just want this for getting to the mainland from time to time.

Going UP in pitch can help your top end, but will also LOWER the RPMs
(higher gear on a car). Going DOWN in pitch will help your LOW end (hole
shot), and will RAISE ypur RPMs and possible over rev.

Something else is holding your speed down.

--Mike

"Josh Assing" wrote in message
...
Hi All.
We just added a power boat to our fleet (of otherwise sailboats)
1990 Four Winns Horizon 180
Cobra outdrive, 4.3L GM engine

The original owner has two zincs; but I can count 4 (it's in the water
right
now) -- QUestion: Does anyone know if there's a zinc behind the prop? Is
there
a place where I can just buy a "zinc kit" for the outdrive?

The "factory" prop is a 14.5 x 19 -- that's what's on there now; max RPM
is
supposed to be between 4200-4600 and running at 42-45mph

The factory prop is on there now -- it's an ugly thing with non-smooth
blades
(they appear welded to the hub) and nicks out of hte blade (ala running
thru mud
etc)

I'm getting at optimium trim 4200rpm but only 30mph. Engine is strong
with good
even compression.

Would going down in pitch (raising RPM) help any with top speed? We're
not
skiers, we just want this for getting to the mainland from time to time.

Oh -- and one thing that really bugs me -- the trim on these boats.... the
trim
guage always reads "UP" I suspect the sender is jammed/broken -- but --
should
it allow you to raise it to "trailer mode" while underway? This is the
1st boat
that's allowed me to do that.

Thanks for any advice
-josh


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Going UP in pitch can help your top end, but will also LOWER the RPMs
(higher gear on a car). Going DOWN in pitch will help your LOW end (hole
shot), and will RAISE ypur RPMs and possible over rev.

Something else is holding your speed down.

Righto.. Thanks.

I knew that going down in pitch would raise the rpm -- but I was wondering if
the increased RPM would help with the top end at all.

Since I'm at the lower end of the RPM range, I'm not sure going up in pitch
would be a wise choice.


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Since I'm at the lower end of the RPM range, I'm not sure going up in
pitch
would be a wise choice.

Going down a couple of inches in pitch will get you to the higher end of
your WOT RPM and should help out the top end a bit. Like I said something
else is keeping the speed down. Have you checked it with a GPS? It's
possible that you're going faster than the speedo shows.

--Mike




"Josh Assing" wrote in message
...
Going UP in pitch can help your top end, but will also LOWER the RPMs
(higher gear on a car). Going DOWN in pitch will help your LOW end (hole
shot), and will RAISE ypur RPMs and possible over rev.

Something else is holding your speed down.

Righto.. Thanks.

I knew that going down in pitch would raise the rpm -- but I was wondering
if
the increased RPM would help with the top end at all.

Since I'm at the lower end of the RPM range, I'm not sure going up in
pitch
would be a wise choice.


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Going down a couple of inches in pitch will get you to the higher end of
your WOT RPM and should help out the top end a bit. Like I said something
else is keeping the speed down. Have you checked it with a GPS? It's
possible that you're going faster than the speedo shows.

"A bit" doesn't sound like much. ;-)

GPS verified speed as near accurate (actually slower than what was reported on
the speedo, but considering the tide -- that would be expected)

Any ideas on what could keep the speed down by 10mph?

The original "Matched Options" book has this listed:

High Performance Propellers
V-6, 3.8, 4.3 Litre "1980 thru" OMC Racker14.5x24 = 50-60mph!

Whole cow; that's fast batman

But up 5" in pitch? yikes; that certainly would bog down & overwork the engine.

The prop does have a few dings in the end.

A trial today with glass like water got me to 35mph @ 4600 rpm; so maybe I will
go up in pitch


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"A bit" doesn't sound like much. ;-)

You're right, just tossin' out ideas.

V-6, 3.8, 4.3 Litre "1980 thru" OMC Racker14.5x24 = 50-60mph!
Whole cow; that's fast batman

Atomic batteries to power...turbines to speed... g

Speaking of props, what material is yours? A few dings will make a
difference, but certainly not 10-15mph. A stainless prop gets a better
"bite" on the water, but is also very expensive (compared to aluminum). I
had a 22p stainless prop on my 4.3L 18' reinell, and she got to about 45mph.
Can you turn the prop by hand at all when it is in gear? I don't know if you
can "partially" spin a prop from it's hub, but if it's slipping under load,
that would certainly account for a lower top end. Slower out of the hole as
well.

--Mike


"Josh Assing" wrote in message
news
Going down a couple of inches in pitch will get you to the higher end of
your WOT RPM and should help out the top end a bit. Like I said something
else is keeping the speed down. Have you checked it with a GPS? It's
possible that you're going faster than the speedo shows.

"A bit" doesn't sound like much. ;-)

GPS verified speed as near accurate (actually slower than what was
reported on
the speedo, but considering the tide -- that would be expected)

Any ideas on what could keep the speed down by 10mph?

The original "Matched Options" book has this listed:

High Performance Propellers
V-6, 3.8, 4.3 Litre "1980 thru" OMC Racker14.5x24 = 50-60mph!

Whole cow; that's fast batman

But up 5" in pitch? yikes; that certainly would bog down & overwork the
engine.

The prop does have a few dings in the end.

A trial today with glass like water got me to 35mph @ 4600 rpm; so maybe I
will
go up in pitch


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I wouldn't worry about the trim guage. My Chris Craft has a trim guage
that does the same thing. If your's is equipped with a "Bow up/down"
switch, I'd run it with the "Bow Down" fully engaged and it should trim
nicely. Or, at least thats what I do.


Josh Assing wrote:
Oh -- and one thing that really bugs me -- the trim on these boats.... the trim
guage always reads "UP" I suspect the sender is jammed/broken -- but -- should
it allow you to raise it to "trailer mode" while underway? This is the 1st boat
that's allowed me to do that.

Thanks for any advice
-josh


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Remove X's to send email to me.

I wouldn't worry about the trim guage. My Chris Craft has a trim guage
that does the same thing. If your's is equipped with a "Bow up/down"
switch, I'd run it with the "Bow Down" fully engaged and it should trim
nicely. Or, at least thats what I do.

The problem is that it doesn't "stop" so if you're not paying attention; you
can trim it up into "Trailer mode" while underway..


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