Re: fuel supply for new 4 stroke
Piece-o-cake. The 6 hp 4-stroke won't need pre-mix and the 115 is oil injected, so they both can run off the existing boat tank.<br /><br />Purchase a fuel filter/water separator with one inlet and two outlets (a two in and two out, used for dual tanks will work if you plug one of the inlets). These units are fairly small and can mount just about anywhere. Some have spin-on filters and others have cartridges and see-through bowls with drains. Racor makes a good one.<br /><br />Run your tank line into the filter unit (if you have dual lines you can put a small marine fuel shut-off valve on each line to alternate use between tanks, to run both, or use as a complete shut-off of both tanks). Then connect each outboad to an outlet on the filter unit. The filter unit will have arrows stamped on it to show in and out.<br /><br />Most of my boats have two outboards and twin tanks. I use this Racor system with two fuel lines coming into the unit with a shut off valve on each line. Then out to each outboard. The lines out of the unit are the lines that have the primer bulb, one for each outboard. I can run either outboard at any time, run them both at the same time, shut one tank off or the other, run off both tanks together, or shut both tanks completely off. <br /><br />Never had a problem. Fuel does not get siphoned from one outboard to the other. I believe the primer bulb acts as a check valve.
