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View Full Version : Does a 496 have a fuel return line ?



26Daytona
07-21-2006, 09:43 AM
Can I run the lines directly from my tanks to the pump, then to a cooler and then the manifold, or do I need some type of return line ?

SoCalSouthpaw
07-21-2006, 09:46 AM
You can pick up a kit at your local auto part store. They're right next to the piston return spring kits.

boater012
07-21-2006, 09:55 AM
Most mercruiser engines route the return line form the fuel injection right to the fuel fitler housing. one of the inlets on the fuel filter comes in from the tank and the other comes in from the return from the fuel rail. the fuel outlet line runs from the fuel filter outlet fitting to the fuel pump! (or in your case through the fuel cooler/ pump combo) BTW if you are hooking this all up yourself, you want to make sure to hook your Water/fuel seperator up as a "draw through" NOT a pressure through. If you "push" the fuel through the filter it will not have a chance to filter the water out.
Btw I have a schematic for the fuel system if you need it! you can also go to www.mercruiserparts.com and see one there as well. go to the search for parts with pictures icon and then find your engine and enter the serial number to get an accurate schematic! Good luck!

Cat & Mice
07-21-2006, 10:04 AM
returning the fuel to the tank is always best to keep the fuel cool. if you recirc within the motors fuel system the fuel that goes into the injector will have passed thru the pump a few times and has been heated. Hot fuel does not work aswell as cool fuel!
If you can return to tank!
MP

Raylar
07-22-2006, 10:30 AM
You need to know which year engine you have.
From 2001 to 2004 the 496's had a cool fuel/fuel pump unit down along the left side of the block near the oil cooler. This unit has a fixed fuel pressure regulator on it and a return line running back from it to the fuel/water seperator on the other side of the motor. the 2004-1/2 and later 496's have a fuel pump/fuel cooler assembly on the lower right front of the motor above the raw water pump. Yhis unit has a fixed fuel pressure regulator in its top cover and it returns the unused fuel internally back to its own fuel cooler resivoir, which means you cant modify it unless you use a whole new fuel pump/fuel cooler and regulator system. On the older 496's you could disconnect the return line from the fuel/water seperator, plug that opening and reroute the return line to a T-fitting in your gas tank fill hose, but I don't think anything would be improved or gained unless you are having a serious fuel heating problem. Age old addage: "If it ain't broke, don't fix it!!
Ray @ Raylar

26Daytona
07-22-2006, 11:56 AM
Thanks Ray