Hose Sizes 1963 75hp

[yorab]

I'm gonna replace all hoses for the motor in my signature. I understand that I need to get alchohol-resistant lines for the fuel. Is there anything special about the water lines, i.e. the lines that run to the hot-water-actuated choke? Anything special about the vacuum lines, i.e. the line that operates the fuel pump?

Also, how do I size the lines. All lines are connected to the various parts of the motor by a nipple. Let's say I measure a nipple at its widest point and it is 1/2". Do I go with 1/2" ID line or do I go down to, say, 7/16" ID line? Or, better yet, is there some resource out there that lists the line sizes by motor and year?

Lastly, should I go with those original single-gauge wire clamps or the newer worm-gear clamps? Thanks.

 

[jtexas]

Re: Hose Sizes 1963 75hp

Fuel line from the car parts store will be fine. If your area is pumping ethanol-blended gas then the parts store will have the right hose. Use fuel hose for the pump pulse line.

I usually take the old hose with me.

The existing clamps are ok. Later models, use zip ties, which work just fine.

 

[yorab]

Re: Hose Sizes 1963 75hp

Okay jtexas, I'll use the auto parts store fuel lines. Do I need anything special for the water lines? I believe that the old hoses are not original and may be incorrectly sized. That's why I'd like to find out the proper way to size them. Also, my motor had the worm-gear type clamps and my parts motor has the original clamps. That why I was wondering which is best. Since neither cost much, I'd prefer to use the best type even if I have to buy new.

 

[yorab]

Re: Hose Sizes 1963 75hp

I found an interesting site about barbed fittings but unfortunately it doesn't give recommendations about line sizing. From reading this, I guess it matters how elastic the lines are and the shape of the barbs. This is more for bio and life sciences, but barbed connections are barbed connections...

http://www.pddnet.com/article-the-science-of-hose-barbs/

 

[yorab]

Re: Hose Sizes 1963 75hp

I've been told to use hose ID that matches the diameter of the nipple behind the barb. This is dimension "A" in my very crude drawing.

 

[boldtr]

Re: Hose Sizes 1963 75hp

Fuel lines / pump line for that motor are 5/16". I bought some alcohol resistant hose from O-Reilly auto-parts for $1.29 per foot. 5/16" will fit snuggly over the barb.