M5B Internal to External Tank Conversion

So I am near completion of converting to an external tank . Two areas that need to be addressed:

1) See picture below as to how the fuel line routes from the connector into the carb. I need to make a 180 degree turn in order to flow this into the carb. Not liking have all this hose inside and the resultant loop. Note this is 1/4 ID line. I'm thinking of two approaches to resolve this a) finding a fuel filter- caniser style - one that is used on some OMC or Suzuki engines where the barb location would result in a 180 turn; b) go to the hardware store and find some brass fittings that could make at least a 90 degree bend (ideally with both ends being barbed as opposed to a barbed and NPT at the other end)

2) Need to buy the line from the external tank into the male fitting, is there any advantage of getting 3/8 v 5/16 hose for this line?

Apparently you intend to eliminate the integral tank. Otherwise, you would be using a fuel divertor valve, and a check valve, in addition to the inline filter. You are using rather cheap, crude, fuel line, typically seen on a lawn tractor. If you use the OEM Tohatsu fuel line, it is much more limber, and you can make a much shorter run from the fuel inlet connector to the carb via the filter. Not too expensive, either:


Your fuel flow rate is so low that the diameter of the primer hose from the external tank is irrelevant. Again, I would recommend using a good-quality oem-style primer hose, as it will remain supple longer.

That crude looking line is only used for "test" purposes as I had some lying around from another "outdoor eqpt project". I am making some modifications to an EPA-cert external tank and wanted to test the tank and line configuration before comitting to finalizing the routing of the fuel line using J1527 standard fuel hose both inside the cowling and of course from the tank to the fuel barb...

Regarding the integral tank, I would like to retain that as an option but could not find the right part to use as a 3 way valve, not the best place to mount the valve such that is is secure.

See your local dealer. You can use the setup that was used on the MFS5A2 4-stroke. Just keep your original valve from your original tank, instead of the valve that operates through the side of the lower cowl.