I want to use a 5hp Briggs & Stratton engine for a kart project. That engine is based on a carburetor that is above the fuel tank, pumping the fuel thanks to the diaphragm.

I am thinking about upgrading it a little bit by changing the carburetor with a carburetor that could use fuel that comes directly, without pumping it. With this, I could use a bigger fuel tank, and "simplify" the carburetor system, leading to a longest autonomy and a simpler system.

Do you have in mind some carburetors that could be compatible ? Is my idea possible or totally bad ?

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Apr 11, 2022 at 23:24

2 Answers 2


You can do exactly what you're talking about. Mainly, you just need to have the gas tank above the carb and let it gravity feed. I'm not sure exactly which carb you have, but most "pumped" carbs like what you're talking about is being done via a vacuum source. Not knowing exactly how this is with your carb, if you can find the diaphragm pump and block it from working, then put the gas above the carb, you should be able to run the carb you have now. You might even be able to do it without disabling the diaphragm pump.

If there is an issue with your carb and it doesn't work at all, you'd need to measure the base attachment area, the venturi opening, and bolt spacing, then cross reference that online to find what you're looking for. There are a lot of sites which sell carbs which also have these mounting specs for the carbs they sell. About the only way I can think of to get you what you're looking for. The only problem you might run into is if a carb you find is not big enough. This might keep it from producing maximum power. It really shouldn't be that big of an issue, though. You should be able to find something.

  • I found that the exact terms for what I am trying to achieve is "carburetor swap". But you say hat I also could keep my actual carb ? But how does the gas goes to the carb ?
    – fallais
    Commented Apr 12, 2022 at 16:22
  • @fallais - With the gas tank above the carb, it is gravity fed. I assumed that is what you were attempt to do. They make pump fed one's like yours with the carb above the fuel tank as a way to compact everything into as tight of a space as possible. You just need a constant source of fuel in order for it to work. Putting the tank above the carb will do just that. Commented Apr 12, 2022 at 17:36
  • Yeah this is what I want to do but I would prefer to swap the whole carburetor and use a "gravity carburetor" instead of the one I have, instead of modifying the actual carb. But the question behind is how to find a compatible carb, that would fit the intake screw holes. This is the engine : laboutiquemotoculture.fr/images/…
    – fallais
    Commented Apr 12, 2022 at 20:57

https://www.amazon.com/Motorcycle-Carburetor-125cc-150cc-175cc/dp/B091CBYH4N?th=1 This might work for you. I'm not sure it would be just a bolt on, but it should run your engine fine. This needs to be connected to a throttle pedal of some kind, where most lawn mower carbs are just connected to a governor.

  • 1
    Thanks, I will take a look at it !
    – fallais
    Commented May 6 at 14:16

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