1978 Merc 700 Fuel Pump Hoses - Where to?

I picked up a boat with this nice looking Merc 700. The fuel delivery was a problem upon taking her out the first time so I pop off the cowl and find that the previous owner bypassed the fuel pump and installed an inline fuel pump to push the gas from the remote gas tank instead. I want to go back to the original. I take apart the fuel pump and it's pretty gunked up - looks like he tried to block the passages with sealant. I got it cleaned up and a rebuild kit for the fuel pump is on its way. I think that should take care of a lot, but the hoses from the fuel pump (large barbs) to the crankcase are totally missing and I can't seem to find where they go to. Can anyone help me? I've poked around the engine for a bit and just can't figure it out or find a diagram anywhere that displays where the hoses should go to.

Thanks in advance!

In short, where do hoses 10 and 12 go to?

Re: 1978 Merc 700 Fuel Pump Hoses - Where to?

Can you post a picture of the fuel pump that you have and the location of it? Some of the early years do have sepreateat hoses that went to the block to make them work while others mated to the block , and no hose was needed. For the ones that need a pluse hose, there should be a fitting on the block or intake usally above and close to where the pump mounts. Being that the PO has modified the setup ,it is posiable that the pump itself has been replaced or modified and is the worng one for the motor. JMO
Oldman570

Re: 1978 Merc 700 Fuel Pump Hoses - Where to?

Thanks for the reply. It looks like it's mamted tot he block and therefore should get crankcase pressure from there - so then what are the two large-bore connections supposed to go to? They are hose #10 and 12 in the diagram I uploaded.

Thanks again!

oldman570 said:

Can you post a picture of the fuel pump that you have and the location of it? Some of the early years do have sepreateat hoses that went to the block to make them work while others mated to the block , and no hose was needed. For the ones that need a pluse hose, there should be a fitting on the block or intake usally above and close to where the pump mounts. Being that the PO has modified the setup ,it is posiable that the pump itself has been replaced or modified and is the worng one for the motor. JMO
Oldman570

Click to expand...

Re: 1978 Merc 700 Fuel Pump Hoses - Where to?

#12 goes to the telltale and #10 come from the exhaust plate on the starboard side.