Fuel Pump Diaphragm Rupture Hose Type?

[76SeaRay]

I know that the main fuel line needs to be marine grade (which I bought) but what about the hose that runs from the fitting on the fuel pump to the carburetor in case of fuel pump leakage? Is there small diameter marine grade fuel hose or is it acceptable to just use automotive vacuum line? Thanks...

 

[AShipShow]

Its tygon tubing... If you're lucky you can find it locally, but I found none of my local hardware or auto parts stores had tygon tubing that big... its usually used on small engines...
I ordered mine online.

 

[poconojoe]

I know that the main fuel line needs to be marine grade (which I bought) but what about the hose that runs from the fitting on the fuel pump to the carburetor in case of fuel pump leakage? Is there small diameter marine grade fuel hose or is it acceptable to just use automotive vacuum line? Thanks...

I wouldn't use vacuum hose for fuel. That sounds like a terrible idea.

 

[76SeaRay]

Fuel doesn't flow through that hose unless there is fuel pump failure and then it will cause the engine to die with too much fuel in the carb. I will see if I can find tygon tubing. I think ACE Hardware carries it.

 

[76SeaRay]

I was just looking at my QJet carb and realized that, although it is a marine carb, I don't have an extra fitting for the fuel pump rupture hose. Do you think I can put a "T" in the line that goes to the choke diaphragm (see black hose on the left side of the pic) to connect the rupture line from the fuel pump?

 

[AShipShow]

No... the hose shouldn't be under vacuum as it will collapse the hose, and maybe even cause problems with the pump diaphram... The hose should enter the carb above the choke plate.. If you don't have any good provision for this, you should convert over to an electric pump..

You could probably rig up a hose that would go through the spark arrestor and make it somewhat "not sketchy" but I won't advise you do this because if it doesn't work as intended, your bilge will turn into a bomb...

 

[Bt Doctur]

if thats a vac fitting on the lower left of the carb, its not marine

 

[76SeaRay]

There aren't any vacuum ports on the carburetor (other than the choke diaphragm). The dark things lower left and lower right are the idle mixture screws.

 

[Scott Danforth]

some older carbs had the tygon line running to a fitting on the spark arrestor.

my OMG was like that

 

[76SeaRay]

I found that Mercruiser at one time had a flame arrestor with the tube fitting built into it so I guess I am ok with adding a fitting to the top of the flame arrestor assuming that is legal with the Coast Guard. I actually need to get another flame arrestor since the one I have does not have vent tubes for the PCV valves on the valve covers. Actually I guess the fittings on the valve covers are really just 90 degree elbows and not really PCV valves.

 

[AShipShow]

Yep, just elbows, not pcv valves...
If I were you, I would try to rig it up so the spark arrestor fits over the fittings and hose in a way that you don't have to remove the tygon hose and hose clamp whenever you want to remove the spark arrestor... that would be a pain...

Thinking maybe some stainless brake line and attach it to the carb and you can custom bend it to go up to the throat of the carb...
Lots of options but try to make it easy for yourself next time you need to work on it....

 

[Scott Danforth]

They sell clip on vent tubes to add hosed to your existing spark arrestor

 

[flashback]

A couple of months ago I converted to an electric fuel pump and removed that hose and if I remember it connected to a small brass fitting that is pressed into the carb body just below the top edge of the carb.

 

[johnkom]

Fuel pump vent line to flame arrestor.

JK

 

[76SeaRay]

Thanks for the pic. I have a flame arrestor with a fitting on the way...

 

[Scott Danforth]

It may look something like this