adding remote fuel tank to yamaha 2.5hp 4 stroke

[Roger (Ninette Manitoba)]

Has anyone plumbed in a connector for a remote fuel tank? This is a loaded question that gets to a basic understanding of this motor. Although it is not difficult to concieve the above retrofit, here is the conundrum... The original motor has an integral fuel tank. Does it also have a fuel pump, or is it just gravity fed? If id does not have a fuel pump diaphragm then there is no way plumbing in a remote fuel source will work. I'd like to hear from anyone who owns one of these motors and knows if indeed there is some kind of fuel pump or diaphragm. Has anyone done this on a similar motor with an integral tank?

 

[Benny17441]

Roger you can still add a remote tank to a

gravity fed engine. It can be quite simple if you can modify the built in gas tank cap. These caps usually have a vent valve that can be closed when the motor is not being used. The idea is to eliminate the valve by drilling out a hole in the cap to be able to insert an out board male tank fitting. The other components needed are the remote tank, a fuel hose with a priming bulb and a female conector to attach to the one you have put on the cap. The operating principle is that as the gas in the built in tank is used it creates a vacum which is used to pull gas from the external tank. To attach the fitting to the cap you need to make a good seal with washers and "o" rings. We have a similar set up with a Honda 2000eu generator and works like a charm. It would work even better with an out board engine as you would be there to supervise it. Even if you could not attain a perfect vacumm with your engine, all you would have to do is every hour squeeze the priming bulb a few times and it would transfer fuel from the external tank to the built in.

 

[sailaway78]

How much do you use it.

I have a little 2hp Suzuki, with internal tank, that holds a little less than a quart. This thing will run for a loooooooooong time on that little amount of fuel. When I'm planning on doing a lot of running, I just throw an extra quart of gas into the dinghy. I can't imagine burning more than that in a day. So it seems like adding an extra tank would not only be a lot of work, but take up a lot of space.

 

[Roger (Ninette Manitoba)]

add on tank

Thanks for your comments there Nice and Easy. I have thought of the extra labor, but experience has taught me that in fact, I have run out of gas a couple of times and had to refuel, sometimes at the most awkward times, ie when just outside the harbour entrance, another time when approaching a lee shore, so I have opted for the extra plumbing and tank for those longer excursions. I do agree that it will run for an hour or so on a tank, but as I indicated earlier, if there is no wind, a run to the far end of the lake and back is 4 hours.Benny, by the same priciple of tank suction, could I not plumb in a make connector to a location adjacent to the tank cap, thereby having a permanant fixture on the tank? I could drill a hole in the cowling that it would slip through. that way I don't muck with the current gas cap, and have a 'cleaner' set up. I really like your idea, it may be the simplest way to do this. Let me know what you think.

 

[Richard]

fuel tank

Yes you can add a fuel tank and no your little motor doesn't have a fuel pump if it is carburated.all you need is a 12volt DC fuel pump from the auto parts store, wire to power it and if it want's to flood the engine you will have to put a pressure reducing regulator in alsoDon't forget about the fuel vapors from the new tank Richard

 

[Stu Jackson]

Good Old Boat magazine

had a reader-provided article on just this about a year or two ago, check their archive index for the story.