Fuel Issue for a 1978 merc 470

bently

Petty Officer 1st Class
Joined
May 24, 2009
Messages
202
This is not really a tread about my 470 but my fuel supply line no longer supplies fuel to the fuel pump. the pick-up hose either disconnected or became brittle and broke. I can pressurize my fuel tank and air will leave through both the vent and fuel supply line. My tank is in the floor which I just completely replaced last year and decided not to recreate the removable piece above the gas tank.........Now I get to cut up my nice, no seems, floor to replace a $1.99 fuel hose.........

sucks.
 

jabfd

Petty Officer 1st Class
Joined
Oct 2, 2012
Messages
221
Re: Fuel Issue for a 1978 merc 470

You should no more or less where the connection on the tank if you just replaced floo
I would use a hole saw to drill the floor In that area then you will see where the fittings. Cut the hole with a jig saw and add a access cover they sell them in many sizes good luck
 

bently

Petty Officer 1st Class
Joined
May 24, 2009
Messages
202
Re: Fuel Issue for a 1978 merc 470

I was able to cut open an access to where the out going fuel line is on the tank.
how does the silver square fitting come out of the tank? Does it just screw out?

Thanks
 

bently

Petty Officer 1st Class
Joined
May 24, 2009
Messages
202
Re: Fuel Issue for a 1978 merc 470

Here is a photo of the fitting.

Gas Tank Fitting 2.jpg
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,344
Re: Fuel Issue for a 1978 merc 470

Are positive you have enough fuel in the tank for the pickup tube to pick it up? its not a hose ,its a tube that goes to the bottom of the tank. usually unscrews from the tank fitting. Tanks are designed to NOT suck up every last drop. could have as much as 10-15 gallons of what is called "unuseable fuel"
 
Last edited:

bently

Petty Officer 1st Class
Joined
May 24, 2009
Messages
202
Re: Fuel Issue for a 1978 merc 470

I was able to drain it almost completely last fall. I put 5 gallons in this spring and the boat is sitting in the same spot so it is in the same level position but now I am just getting air out of the tank. That is why it seems wrong/different. So that fitting will just screw out so I can atleast check it?

Thanks
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: Fuel Issue for a 1978 merc 470

Yes! and that might be your anti-siphon valve.
 
Top