Prop clearance specs?
 

"Short Wave Sportfishing" wrote in message
...
On Mon, 14 May 2007 12:02:21 GMT, "jamesgangnc"
wrote:

Are you completely sure the motor is running at it's best? You didn't
give
much info but I'm thinking at one time the prop you have on it may have
been
correct. I agree about the size, you want something between 14 and 14.5.
I
think the 15s were common on the bravos. If you want to experiment buy
used
props off ebay. You can resell them for about what you paid for them.

That was my thought - something ain't right there.

Good idea on that eBay thing - although I'm not much of a eBay type.

Anybody know how selling on eBay works - per chance?

I've never done it, but I've got some motorcycle parts from my
youngest's GSX R600 - stock parts - that I want to get rid of, sell,
swap - whatever.

I can walk you through it if you still need help. Let me know and I will
email you my phone number.

Prop clearance specs?
 

On May 12, 11:47 am, Josh Assing wrote:
I have a alpha1 gen II outdrive.
As some of you know; I'm trying to reprop -- found a shop nearby that
rents demo props. They gave mea 15" prop (diameter) but I didn't try it as the
clearance between the prop blade edge and the cavetation plate was less than a
wire-coat hanger.

They said "it improves performance, use it anyway" My gut says that the
clearance is so small that it's begging for damage from a twig in the water.

Two people (one I consider knowledgeable and one from a shop I use regularly)
said "that's not enough clearance, should be about 10% of the prop diameter"

To me - -this sounds reasonable.

So; since the shop with the demo props doesn't want (for unknown reasons) to
give me a 14 or 14.5 diameter prop, I'm stuck with buying a new one; for that
reason; I'm looking to the NG for people that have "almost no clearance" between
the blade & the cavetation plate to see real-world experiences.

We're talking a SS prop. If I guy a prop; I'll probably go with aluminum 1st
(cheaper) while I experiement and then go SS once I settle on size & pitch &
blade count.

Thanks
-j

You might want to consider reducing your trial and error process time
by visiting the Michigan Wheel site and supplying the particulars of
your specific boat. That will let you know what Michigan Wheel would
recommend, and they likely know more about what prop is ideal for your
specific setup than even most knowledgeable prop shops.

http://www.miwheel.com/MIWheel/propit/main.htm

Prop clearance specs?
 

Are you completely sure the motor is running at it's best? You didn't give

Considering it has 420 hours on it -- it's definately NOT running at it's best.
it is, however, running as best as it can w/o a full rebuild.

much info but I'm thinking at one time the prop you have on it may have been
correct. I agree about the size, you want something between 14 and 14.5. I

I'm assuming the boat came from the factory with the correct prop. Since I
doubt it came from the factory with a SS prop, we can assume one of the previous
owners changed it to this one -- which is incorrect.

a 14.5 would fit, the 15 just seems way too close to the plate.

thanks
-josh


think the 15s were common on the bravos. If you want to experiment buy used
props off ebay. You can resell them for about what you paid for them.

"Josh Assing" wrote in message
.. .
I've never had a tach go bad -- but I'll check it out with my old analog
meter
and see what it ways...

On Sun, 13 May 2007 11:00:35 GMT, Short Wave Sportfishing

wrote:

On Sat, 12 May 2007 13:40:08 -0700, Josh Assing
wrote:

And ten percent of a 15 inch diameter prop would be what?

exactly - -it's not 3 mm


That is way to close for a number of reasons including cavitation.

that's what I thought -- the demo-prop-shop said "it will increase
performance
by directing more water aft rather than up" seemed snake-oilish to me.


What you are looking for is a 14.5/21p or thereabouts - might need a
19p - doubt if you will need a 23.
well; wrong way -- I have 19pitch now; need to go down in pitch to 17 or
16.
(wot now = 4100, need to get it to 4400-4600)

Whoops - sorry - read that wrong. My bad.

I think you are probably close on that, but you might want to consider
having the rpm checked using a meter directly off the engine. I know
when I swapped engines on the Ranger, we couldn't get 5400 top end out
of the gage on the dash, but when we looked at the EMM, it was 5400 on
the nose. It was about the same RPM range you noted.

Threw a new RPM gage in the dash - presto.

Just something to think about.

Prop clearance specs?
 

On 14 May 2007 08:18:41 -0700, Chuck Gould wrote:


You might want to consider reducing your trial and error process time
by visiting the Michigan Wheel site and supplying the particulars of
your specific boat. That will let you know what Michigan Wheel would
recommend, and they likely know more about what prop is ideal for your
specific setup than even most knowledgeable prop shops.



I *have* used that -- it says a 14.5x21 is what I need - however, it doesn't ask
me anything about my current performance, unlike the mercury prop site.

Anyway; -- I can't find a 14.5" x 17 prop that is a good performer -- I'm
getting ready to buy a 15x17 prop and have the blades shaved down a 1/4 inch...

Prop clearance specs?
 

On May 12, 3:44 pm, Short Wave Sportfishing wrote:
On Sat, 12 May 2007 11:47:05 -0700, Josh Assing
wrote:

Two people (one I consider knowledgeable and one from a shop I use regularly)
said "that's not enough clearance, should be about 10% of the prop diameter"

And ten percent of a 15 inch diameter prop would be what?

1.5"

Prop clearance specs?
 

Rebuild after 420 hours? What is this a cast aluminum Briggs and
Stratton?

I didn't say it NEEDED a rebuild; I'm saying the only way to get it to run
better would be for a full rebuild....

The boat runs fine -- doesn't leak or burn oil.
It has good even compression.

the engine isn't the issue.

Prop clearance specs?
 

On May 15, 9:04 am, Josh Assing wrote:
On 14 May 2007 08:18:41 -0700, Chuck Gould wrote:

You might want to consider reducing your trial and error process time
by visiting the Michigan Wheel site and supplying the particulars of
your specific boat. That will let you know what Michigan Wheel would
recommend, and they likely know more about what prop is ideal for your
specific setup than even most knowledgeable prop shops.

I *have* used that -- it says a 14.5x21 is what I need - however, it doesn't ask
me anything about my current performance, unlike the mercury prop site.

Anyway; -- I can't find a 14.5" x 17 prop that is a good performer -- I'm
getting ready to buy a 15x17 prop and have the blades shaved down a 1/4 inch...

You can't find a 14 or 14.5 by 17 prop???? That's a little hard to
believe.

Doing anything to an ss prop with be about $150. I think you ought to
look a little harder for the right prop to start with.

Prop clearance specs?
 

On May 16, 7:55 am, jamesgangnc wrote:
On May 15, 9:04 am, Josh Assing wrote:

On 14 May 2007 08:18:41 -0700, Chuck Gould wrote:

You might want to consider reducing your trial and error process time
by visiting the Michigan Wheel site and supplying the particulars of
your specific boat. That will let you know what Michigan Wheel would
recommend, and they likely know more about what prop is ideal for your
specific setup than even most knowledgeable prop shops.

I *have* used that -- it says a 14.5x21 is what I need - however, it doesn't ask
me anything about my current performance, unlike the mercury prop site.

Anyway; -- I can't find a 14.5" x 17 prop that is a good performer -- I'm
getting ready to buy a 15x17 prop and have the blades shaved down a 1/4 inch...

You can't find a 14 or 14.5 by 17 prop???? That's a little hard to
believe.

Doing anything to an ss prop with be about $150. I think you ought to
look a little harder for the right prop to start with.

Just out of curiosity. What rpm are you turning at wot with the prop
you have? And what engine do you have?

Prop clearance specs?
 

Just out of curiosity. What rpm are you turning at wot with the prop
you have? And what engine do you have?

4100 RPM -- should be 4400-4600
That's in a PERFECT day.. flat water, no weight, etc etc etc.
Hole shot sucks.

5.7 gm based mercruiser (350ci) Alpha1 1.47ratio, 19" pitch 3 blade

Regarding the prop -- yes; I can find a 14" 17pitch prop; but they're on the
cheaper side of performance... When I get into 4 blades, they seem to get bigger
as the pitch is decreased.

I'm sure I'll find it.. the prop shop said they wouldn't charge me much to take
some off the edge if I need them to; so I'll probably go with an aluminum and
have them shave it if needed.

-j

Prop clearance specs?
 

Josh Assing wrote:
Just out of curiosity. What rpm are you turning at wot with the prop
you have? And what engine do you have?


4100 RPM -- should be 4400-4600
That's in a PERFECT day.. flat water, no weight, etc etc etc.
Hole shot sucks.

5.7 gm based mercruiser (350ci) Alpha1 1.47ratio, 19" pitch 3 blade

Regarding the prop -- yes; I can find a 14" 17pitch prop; but they're on the
cheaper side of performance... When I get into 4 blades, they seem to get bigger
as the pitch is decreased.

I'm sure I'll find it.. the prop shop said they wouldn't charge me much to take
some off the edge if I need them to; so I'll probably go with an aluminum and
have them shave it if needed.

-j


I am running props from these guys.

http://www.propcopropellers.com/information.htm

Since you have a merc

http://www.propcopropellers.com/mercruiser_Props.htm

they use a traditional rubber hub.

Good Luck

Capt Jack R..