Through Transom Water Hose/Pipe

[SeattleMatt]

So I have a project where I have replaced the gimbal housing on a 1996 Bravo I, the replacement gimbal housing came with a plastic through transom water pipe, whereas the old transom had the standard 3/4 water hose with the tapered insert on both ends of it, and I housing with the hose Outlet to connect to the existing 1 1/4 water hose which goes to the engine mounted impeller. The problem is the new design with the plastic pipe is too small for the larger water hose so I need to step down to that size for it to fit on the plastic pipe. Am I doing this wrong? Should I just get another piece of hose and put a hose clamp around both layers to make the size? Or is there some other method that is in the design?

 

[SeattleMatt]

No Title

 

[alldodge]

That fitting isn't right, what was the part number?

 

[Fun Times]

That's for an Alpha gen 2...Part number 32-416721 http://www.bing.com/images/search?q=32-416721&FORM=HDRSC2

It should look more like item 20, http://www.mercruiserparts.com/bam/s.../30968/5398/60

Are you sure it's an Bravo transom assembly and not an Alpha? Have the T/A serial number handy?
What engine model are you planning on using?

 

[SeattleMatt]

I fear you may be correct, the transom housing I purchased appears identical to the previous Bravo I I have aside from the water hose.

I don't know where to find the part number on the transom housing.

According to this thread http://forums.iboats.com/forum/engi...onvert-an-alpha-gen-2-to-accept-a-bravo-drive

the only thing I should have to check is if the trim ram pins will fit, if not then I guess I will have some reaming to do :/

 

[SeattleMatt]

Just checked, and I realize that actually even that doesn't matter since I'm reusing the Bravo gimbal ring.

So the only question now is is there really a problem using the alpha style plastic pipe to fit to the Bravo impeller.

 

[alldodge]

So the only question now is is there really a problem using the alpha style plastic pipe to fit to the Bravo impeller.

Yes very much so, the alpha pushes water up thru the drive. Pushing water only needs a soft wall hose. The alpha does not supply the same amount of water the external Bravo pump does.

The Bravo pump sucks more then the alpha and therefore needs more volume, reason for the larger hose and that it is hard wall.

 

[SeattleMatt]

There are 2 factors here

1. size: the inner diameter of the 6 inch long plastic pipe is just shy of 3/4 which is the same size of the standard rubber hose that goes from the bell housing to the gimbal housing already, if the hose starts off at 3/4, could 6 more inches really make much of a difference in flow?

2. sucking/pushing: the plastic tube is rigid, so I don't see how pressure one way or another would be a problem in this case.

I'm about to drop the engine back in, everything is already assembled, I would have to disassemble the gimbal housing again, I just replaced, order ANOTHER new water hose, 2 tapered fittings, (since I cut it to fit the plastic tube) and probably the gimbal housing inside elbow (since I can't seem to locate the original) all of which will take at least another week for shipping, the motor has to be in the boat by Friday, so it is just not possible at this point.


I wish I'd caught this earlier, but at this point I don't see myself tearing it apart again.
I think I'm going to have to take a chance that the water flow will be the same with such a small variance in the piping, I just need to find a way to step down to the plastic tube size from the giant 1.25inch hose.

By design it would have made more sense if Merc had created the entire hose run as 1.25 instead of just the interior, since the exterior hose is exactly the same as Alpha, I'm not sure how they expect to get much more flow from the plumbing. Of course then they would really have had to made different bell housing and gimbal housing.

 

[SeattleMatt]

Ok, I bought the parts,

Water Hose Sierra Part Number: 18-3603
Elbow 22-43828T
Elbow Gasket 27-441081
Tapered Insert 41674T

The Sierra version of the water hose does not come with the tapered inserts or the tool, and has a higher price at $35
They did not have in stock the overpriced Sierra 18-9844 Tapered Insert Tool, which is $30 by itself, so I'll have to improvise there. I suggest anyone to order the GLM part 47130 which comes with 2 tapered inserts and the tool.