Hello,
I hope I can get some advice on what to do about my problem. I have an old
15 foot, 70-something Bayliner that I have inherited. (Was that stupid to
take it or what?) Anyway, I recently bought a replacement 50hp motor for
the boat (long story about what happened to the other one) off Craigslist.
The motor is nearly identical to the one that it was replacing, but after
using it a few times I realize that it is about 6 inches shorter than the
old motor.
I was wondering why it wouldn't plane, and sounded as if it was cavitating
and ventilating - it was! It works fine at low speeds, but when I go full
power I get a little push then it slows as the prop sucks air and doesn't
get a good bite of water.

So, after closer examination, fiddling with the trim, and saying bad things
to it....I realize that I'm dealing with a motor that is about 4-6 inches
shorter.

Is there anything I can do to solve this problem short of buying a longer
motor or shortening the transom of the boat? I was thinking of one of those
hydroplane fins like this:
http://www.westmarine.com/webapp/wcs...man/asc/0/grid

but not sure how that would work. As you can see in the photos (links
below), the cavitation plate is above the keel of the boat, although when
running, it's right on the surface of the water.

Side view of engine and mounting:
http://home.comcast.net/~tegwilym/boat/motor-side.jpg

Rear-on view showing cavitation plate location in refrence to the keel -
about ~3 inches above the keel. (arrrghh!)
http://home.comcast.net/~tegwilym/boat/motor-back.jpg


Side view showing location of prop/cavitation plate in relation to the keel:
http://home.comcast.net/~tegwilym/boat/Motor-close.jpg

The mount doesn't seem to have any vertical hight adjustment as far as I can
see. The motor is about a 1965 vintage Mercury 50hp.

Does anyone have advice for a newbie motorboat owner who is learning a lot
in the last few weeks from mistakes??

Any advice - or pointing and laughing - is welcome! :-)

Thanks!


Tom
Remove the "_REMOVE_" in my address to reply directly

Tom wrote:

Hello,
I hope I can get some advice on what to do about my problem. I have an old
15 foot, 70-something Bayliner that I have inherited. (Was that stupid to
take it or what?) Anyway, I recently bought a replacement 50hp motor for
the boat (long story about what happened to the other one) off Craigslist.
The motor is nearly identical to the one that it was replacing, but after
using it a few times I realize that it is about 6 inches shorter than the
old motor.
I was wondering why it wouldn't plane, and sounded as if it was cavitating
and ventilating - it was! It works fine at low speeds, but when I go full
power I get a little push then it slows as the prop sucks air and doesn't
get a good bite of water.

So, after closer examination, fiddling with the trim, and saying bad things
to it....I realize that I'm dealing with a motor that is about 4-6 inches
shorter.

Is there anything I can do to solve this problem short of buying a longer
motor or shortening the transom of the boat? I was thinking of one of those
hydroplane fins like this:
http://www.westmarine.com/webapp/wcs...man/asc/0/grid

but not sure how that would work. As you can see in the photos (links
below), the cavitation plate is above the keel of the boat, although when
running, it's right on the surface of the water.

Side view of engine and mounting:
http://home.comcast.net/~tegwilym/boat/motor-side.jpg

Rear-on view showing cavitation plate location in refrence to the keel -
about ~3 inches above the keel. (arrrghh!)
http://home.comcast.net/~tegwilym/boat/motor-back.jpg


Side view showing location of prop/cavitation plate in relation to the keel:
http://home.comcast.net/~tegwilym/boat/Motor-close.jpg

The mount doesn't seem to have any vertical hight adjustment as far as I can
see. The motor is about a 1965 vintage Mercury 50hp.

Does anyone have advice for a newbie motorboat owner who is learning a lot
in the last few weeks from mistakes??

Any advice - or pointing and laughing - is welcome! :-)

Thanks!


Tom

Trade your 15" outboard for a 20" outboard. Craig's List, eBay, look
around...

Did you keep your old outboard?

Rob

Yeah, I do have the old motor still. It's badly corroded from salt water
and overheated so it won't run. Good for parts though- external only.

I did think of the Craigslist trade, not a bad idea really. I could offer
the old motor along with it as a bonus!

Tom

Trade your 15" outboard for a 20" outboard. Craig's List, eBay, look
around...

Did you keep your old outboard?

Rob

Also look around for a burned out, busted, 20 inch .....but otherwise
good-for-parts motor that matches the 15 inch legged motor that you have.
RG

Tom,

You may be able to move parts from your old motor to the new motor to
make it a longer shaft. If they are identical. If not I would buy one
of these extension kits.

http://www.marineparts.com/partspage...ories/acc8.htm

They are very easy to install.

Good luck

Paul



Tom wrote:
Hello,
I hope I can get some advice on what to do about my problem. I have an old
15 foot, 70-something Bayliner that I have inherited. (Was that stupid to
take it or what?) Anyway, I recently bought a replacement 50hp motor for
the boat (long story about what happened to the other one) off Craigslist.
The motor is nearly identical to the one that it was replacing, but after
using it a few times I realize that it is about 6 inches shorter than the
old motor.
I was wondering why it wouldn't plane, and sounded as if it was cavitating
and ventilating - it was! It works fine at low speeds, but when I go full
power I get a little push then it slows as the prop sucks air and doesn't
get a good bite of water.

So, after closer examination, fiddling with the trim, and saying bad things
to it....I realize that I'm dealing with a motor that is about 4-6 inches
shorter.

Is there anything I can do to solve this problem short of buying a longer
motor or shortening the transom of the boat? I was thinking of one of those
hydroplane fins like this:
http://www.westmarine.com/webapp/wcs...man/asc/0/grid

but not sure how that would work. As you can see in the photos (links
below), the cavitation plate is above the keel of the boat, although when
running, it's right on the surface of the water.

Side view of engine and mounting:
http://home.comcast.net/~tegwilym/boat/motor-side.jpg

Rear-on view showing cavitation plate location in refrence to the keel -
about ~3 inches above the keel. (arrrghh!)
http://home.comcast.net/~tegwilym/boat/motor-back.jpg


Side view showing location of prop/cavitation plate in relation to the keel:
http://home.comcast.net/~tegwilym/boat/Motor-close.jpg

The mount doesn't seem to have any vertical hight adjustment as far as I can
see. The motor is about a 1965 vintage Mercury 50hp.

Does anyone have advice for a newbie motorboat owner who is learning a lot
in the last few weeks from mistakes??

Any advice - or pointing and laughing - is welcome! :-)

Thanks!


Tom
Remove the "_REMOVE_" in my address to reply directly

Thanks for the link! I was wondering if that was an option, but wasn't
sure. I bet that costs more than I spent on the new motor though ($300 on
Craigslist).
I have taken the bottom apart before on the old motor to replace the
impeller (after it was too late!) so I'm familiar with how it goes together.
Kind of a pain to get off, but easy enough.

Tom

"Paul" wrote in message
oups.com...
Tom,

You may be able to move parts from your old motor to the new motor to
make it a longer shaft. If they are identical. If not I would buy one
of these extension kits.

http://www.marineparts.com/partspage...ories/acc8.htm

They are very easy to install.

Good luck

Paul



Tom wrote:
Hello,
I hope I can get some advice on what to do about my problem. I have an
old
15 foot, 70-something Bayliner that I have inherited. (Was that stupid to
take it or what?) Anyway, I recently bought a replacement 50hp motor for
the boat (long story about what happened to the other one) off
Craigslist.
The motor is nearly identical to the one that it was replacing, but after
using it a few times I realize that it is about 6 inches shorter than the
old motor.
I was wondering why it wouldn't plane, and sounded as if it was
cavitating
and ventilating - it was! It works fine at low speeds, but when I go
full
power I get a little push then it slows as the prop sucks air and doesn't
get a good bite of water.

So, after closer examination, fiddling with the trim, and saying bad
things
to it....I realize that I'm dealing with a motor that is about 4-6 inches
shorter.

Is there anything I can do to solve this problem short of buying a longer
motor or shortening the transom of the boat? I was thinking of one of
those
hydroplane fins like this:
http://www.westmarine.com/webapp/wcs...man/asc/0/grid

but not sure how that would work. As you can see in the photos (links
below), the cavitation plate is above the keel of the boat, although when
running, it's right on the surface of the water.

Side view of engine and mounting:
http://home.comcast.net/~tegwilym/boat/motor-side.jpg

Rear-on view showing cavitation plate location in refrence to the keel -
about ~3 inches above the keel. (arrrghh!)
http://home.comcast.net/~tegwilym/boat/motor-back.jpg


Side view showing location of prop/cavitation plate in relation to the
keel:
http://home.comcast.net/~tegwilym/boat/Motor-close.jpg

The mount doesn't seem to have any vertical hight adjustment as far as I
can
see. The motor is about a 1965 vintage Mercury 50hp.

Does anyone have advice for a newbie motorboat owner who is learning a
lot
in the last few weeks from mistakes??

Any advice - or pointing and laughing - is welcome! :-)

Thanks!


Tom
Remove the "_REMOVE_" in my address to reply directly