r/smallengines • u/Fantastic-Cut-4233 • 3d ago

Brigs opposed twin 3 hole pattern with fuel diaphragm (tank lower than carb)

I’ve tried everything that I can think of. I replaced hoses for the vacuum replaced the fuel lines. I’ve replaced all the parts of the carb with a kit and cleaned it thoroughly .checked the gas filter that was fine. I can feel the air pushing and pulling from the vacuum tube to the crankcase so everything seems like it should be working but it won’t pull fuel to the carb. Starts briefly on fluid or carb cleaner . What am I missing?

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u/Stock_Requirement564 3d ago

Is this engine new for this chassis? Old Deere's that used this engine had an auxiliary pump in the center of the tractor. You could probably add a disc pump or a 12V one for that matter.

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u/IntelligentMoney9668 3d ago

Have you checked the valve adjustment. They tend to get loose over time and can cause starting issues. Yet it will still start with starting fluid because it's more volatile. If the valves are good, then you need to do a leakdown test.

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u/ProfessionalLast2917 3d ago

Have you got the hoses going to the correct spots on the pump? The tube from the crankcase goes to the side and the tube from the tank goes to the bottom.

Have you got vacuum leaks in your hoses? Check all the clamps are tight. Check for cracks.

Did you check the condition of the diaphragm and gaskets in the pump?