alpha to bravo

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
do I require a bravo trim pump?

Is there a explanation on the install of the sea pump pic up and its ideal location. the factory manual doesnt cover this where i am looking
 

havasuboatman

Ensign
Joined
Mar 5, 2009
Messages
904
Re: alpha to bravo

You do not need a bravo trim pump.
You want the water pump to be as low as possible in the boat. Bravo water pumps are very easily damaged when run dry. The higher a water pump has to draw the water, the longer it runs dry.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: alpha to bravo

do I require a bravo trim pump?

Is there a explanation on the install of the sea pump pic up and its ideal location. the factory manual doesnt cover this where i am looking


The trim pump is the same. What engine are you putting it on? v-belt or serpentine?

Every now and then I see Bravo raw water pumps on ebay complete with mounting bracket. You probably need the one that doesn't have the fuel pump mount?


Regards,


Rick
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

not sure where your looking;
i was able to buy and use all mercruiser stock parts when i swapped my alpha 1 for a bravo 3. mount the sea water pump in the stock location for your motor
you should be able to find every thing you need in a parts break down.
all you need to do is hook up the black and gray hydraulic hoses for your trim pump the same as they are now on your alpha...dont change any thing there.
this is a pic of the bracket, belt, pulley, and pump i got for mine. the bracket brace isnt in this pic
URL=http://good-times.webshots.com/photo/2822635490103006965gBNgaH]
2822635490103006965S500x500Q85.jpg
[/URL]
 

jtybt

Senior Chief Petty Officer
Joined
Aug 5, 2009
Messages
730
Re: alpha to bravo

I think if y'all read, he's talkin' about a TRIM pump!!!

Depends on what you're working on. There are many different early trim pumps. The newer ones may have different fittings.. Hoses are different lengths. Reverse cut-out is in the pump compared to early reverse cut-out.

If you're swapping an alpha drive to Bravo drive, there are a lot more differences...in fact, everything is different.
 

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
Re: alpha to bravo

thanks for the fast answers. I have a fresh 454 that I just had re-built with v belts. I have an 89 alpha setup and I have been getting the bravo parts bit by bit and have the sea pump yet to aquire and wanted to know if I use the existing trim pump. I guess mine will work providing the hoses work with it. I was just given 2 gallons of white epoxie paint and two gallons of clear so I will be painting boat. Thought it best to do the drive after as I can paint with outdrive gear out of the way.

Why do I need a sea pump when I have a water pump on the block?
What if any are the differiences with the bravo outdrive in respect to water passages, exhaust, and oil passages?

Any alignment tricks? I have the alignment bar but are there any existing holes the alpha trans assembly leaves to help the bravo alignment? I read two additional holes will be needed does that mean the rest line up? are there any I should fill? Does the bravo outdrive have the same overall configuration in the mounting as the alpha? Are they the same size?

Thanks
 
Last edited:

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: alpha to bravo

The gimbal housing is what requires the additional two holes to be drilled on a Bravo, the rest of the holes line up. The outdrive itself is bigger and heavier, but not by enough to make much of a difference.
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

the sea pump is needed because the motor pump wont pick up enough if any water from the lake-sea to cool.
you can use the exhaust and y pipe from the alpha.
you will need to change-
motor shift plate
engine coupler and coupler cover-bell housing
add sea pump
drill the two more 5/8" holes for bravo transsome mount
bravo transom assembly.
your sea water pump will plumb in right where your alpha did (mine was at the oil cooler)
the bravo drive will be close to the alpha but bigger and heaver. the cav plate on my b3 was the same height as the alpha i too off.

the front motor mounts are the same on both and lineament is done the same way on both

as stated above the trim pump on mine was the same on both and didnt need changed
 

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
Re: alpha to bravo

tnks jax.

The guy I bought the bravo stuff from said my coupling would work as is?
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

to answer, it will spline on and work. but you realy need to change to the bravo coupler
the bravo is a lot heaver duty and if it fails then your back to a motor pull to fix. not that much to change now and be safe.
here is a pic of the two

URL=http://good-times.webshots.com/photo/2247395070103006965qYlgNL]
2247395070103006965S600x600Q85.jpg
[/URL]
 

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
Re: alpha to bravo

ok i see
mine will work but merc updated the strength on the new one. I will get the right one. Dont want to pull the stove just for that

. Thanks for the pictures and the heads up.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: alpha to bravo

as stated above the trim pump on mine was the same on both and didnt need changed
Yeah, I even considered using the old OMC Cobra trim pump!! (That would have been BAD JUJU!)

The pictures tel the story. You can usually find a new coupler on ebay for
about $300 or less...


You're gonna LOVE that Bravo!!
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

just rember if you have the alpha coupler and you change to the bravo, you have to change the the, mercruiser calls it, the flywheel housing.

as you can see, the alpha is quite a bit smaller. the fly wheel housing fits tight around it and so the bravo coupler wont fit under it.
 

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
Re: alpha to bravo

tnks again jax

i will start getting thoes parts together
 

jtybt

Senior Chief Petty Officer
Joined
Aug 5, 2009
Messages
730
Re: alpha to bravo

The coupler bolt pattern is for the 14" flywheel...just in case you have the 12". You either have to get the coupler drill from a machine shop to fit a 12" wheel or get a 14" wheel.

There is a difference in rear motor mounts. There are two different different rubber inserts. There is also a difference in the position of the inner transom assembly motor mount compared to the alpha...it matches the bravo bell housing(coupler housing).

Like I said...nothing is interchangable.
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

charlie; for his year they should be the same.
the bolt pattern for my alpha and the brave were the same. the alpha just used 3 more bolts and they were already drilled on my flywheel.
the transom rear mounts were in the same place(i tried the alpha on the bravo T A and vice verca) and the only difference in the flywheel housing was the size of the hole for the coupler to stick out of. the alpha flywheel housing fit on the bravo transom and the coupler splines are the same on both. i could have used the alpha coupler and housing but chose not to due to the difference in construction of the bravo.

my stuff was all for a 7.4L but when i checked a 350 cid would have been the same. i considered changing the motor to a small block and keeping the alpha instead of changing drives.
 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

here are a before and after pic of inner T A. white alpha and black is bravo




 

jaxnjil

Lieutenant
Joined
Aug 3, 2007
Messages
1,368
Re: alpha to bravo

the inner transome plate on the two are different. i just considered the inner transome plate as part of the transome and it should come as unit with both.
 

toolsinbox

Petty Officer 2nd Class
Joined
Apr 22, 2009
Messages
187
Re: alpha to bravo

the trans plate i got with the bravo stuff has part number 94986
 
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