Alpha One Gen One Trim Pump Hydraulic Line Identification and Orientation

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San_Diego_SeaRay

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Rebuilding a mid-80s Alpha One Gen One Transom assembly and I forgot to mark the trim pump hoses. Now I'm reinstalling them and I'm confused which is which. Seems like online resources contradict each other as to which hose is which. The questions I'm trying to answer are:
  • Which is the high pressure (UP) hose and which is the lower pressure (DOWN) hose?
  • When installing into the hydraulic manifold, which hose is aft and which hose is forward? Does it matter?
Someone told me that the "lighter" hose once had a grey rubber exterior, but that it has been worn/peeled/cracked away with time. Now there's just a cloth type sheath that you see in the picture.

th
 
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Fun Times

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Fun Times

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Wrong, grey is up see post 8
One thing Don (and I) always mentioned (surprised he did this himself) is you can not use/go off of a parts diagram for correct directions/placement as they are typically backwards. If you fully read the manuals, they'll show the opposite of the parts catalogs.

Page 6 - 8 and 13 Power Trim all say/show, http://www.boatfix.com/merc/Techbk/97/97hs6.pdf
1 - “In”/“Down” Hydraulic Hose (Gray)
2 -“Up”/“Out” Hydraulic Hose (Black)
 
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San_Diego_SeaRay

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Left side is up....Right side is down also the pump adaptor assembly by/at the hose connectors are sometimes marked Up and Dn but hard to see when dirty.
Hopefully this is the design pump you have

Thanks for the picture assistance guys. Much appreciated. :cool:

*If* I can figure out which hose is high pressure and which hose is low pressure, I *think* everything should sort itself out. Here's my logic: In Post #9 of the link to the thread that both of you provided, a very good point is made. The forward ports on the hydraulic manifold are connected via a hose to the up port on the trim ram (the up port must be at the forward end of the trim ram, right? (Part #3 is the hose that connects these two ports)). So this would answer my second question that I posed. So we now know that the high pressure hose goes on the forward end of the the hydraulic manifold, and therefore the aft end of the manifold must be the low pressure.

I have a new trim pump that clearly marks the "up" and "down" ports. So all that's left to figure out is which hose was built for high pressure. From there, I'll know where it goes on the manifold and also where it goes on the trim pump. Does that sound reasonable or am I missing something?
 
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Fun Times

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*If* I can figure out which hose is high pressure and which hose is low pressure, I *think* everything should sort itself out.
I have a new trim pump that clearly marks the "up" and "down" ports. So all that's left to figure out is which hose was built for high pressure. From there, I'll know where it goes on the manifold and also where it goes on the trim pump. Does that sound reasonable or am I missing something?
Sounds like a good plan to me.:) http://www.amarket.com/im5129.htm

[h=1]BOTH 48 INCH TRIM LINES[/h]
FOR 86 UP OILDYNE TRIM PUMPS​
GRAY DOWN LOW PRESSURE LINE​
PLUS BLACK UP HOSE​
im5129.jpg
 

Bt Doctur

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Looked at the pump this morning and I concur Fun Times findings Left,Black ,Up
 

Alumarine

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When the grey rubber exterior comes off would that indicate that it's time for a new hose or is it more cosmetic?
Just curious.
 

San_Diego_SeaRay

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Looked at the pump this morning and I concur Fun Times findings Left,Black ,Up

Thanks Ed and Fun Times. So I'm gonna go with "black = up = high pressure" and "gray = down = low pressure".

As an added confirmation, I dug up an old picture from last year where the gray hose does seem to be aft of the black hose, which would concur with your conclusions:

th

th
 
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Fun Times

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When the grey rubber exterior comes off would that indicate that it's time for a new hose or is it more cosmetic?
Just curious.
My personal view would depend on the overall condition of the hose such as heavy cracks, splinters, etc. deep into the construction of the hose along with how pliable it is without adding more cracks, etc. due to usually it's just the outer layer coating that tends to wear off first on the gray hose since the black hose seems to have a better type coating possibly a UV coating like other similar type trim hoses use elsewhere.
 

Alumarine

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My personal view would depend on the overall condition of the hose such as heavy cracks, splinters, etc. deep into the construction of the hose along with how pliable it is without adding more cracks, etc. due to usually it's just the outer layer coating that tends to wear off first on the gray hose since the black hose seems to have a better type coating possibly a UV coating like other similar type trim hoses use elsewhere.

Thanks for the explanation.
I have noticed as well the gray hose loses it's cover before the black one even though most never see daylight.
 
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