WEED EATER DIES WHEN THROTTLED FULL
WEED EATER DIES WHEN THROTTLED FREE

This problem is easily resolved by bending back the metering lever to ensure the plunger can easily reach it. If the fuel cannot come out quick enough to supply the engine, we find ourselves once again with an uneven air fuel ratio, unable to provide enough fuel to keep the engine from bogging down. This means the needle valve will not be lifted as high enough to allow the correct amount of fuel to come out. If the lever is set too low the plunger on the diaphragm will not be able to reach the lever as efficiently as it should be able to. The lever, being made of metal, can be set to different angles. When the diaphragm presses down, the plunger pushes on the back of the lever to allow the correct amount of fuel to come through. Providing the gasket is okay, to fix this problem simply ensure the screws at the top of the machine are nice and tight. Because of the gap, you will lose the vacuum that allows the metering diaphragm to be drawn down, meaning the metering needle will no longer work and it will not allow any fuel to come through from the pump diaphragm area. You'll know if this has happened to your carburettor because even if you cannot see the gap, you'll be able to see the fuel leaking from the reservoir. If there is a gap between the metering diaphragm and the gasket, then additional air can to be sucked in, creating an unbalanced air fuel ratio. The metering diaphragm presses down on the lever allowing the piston to be lifted off. When fuel is used from of the fuel reservoir beneath it, it draws the diaphragm down, allowing more fuel to enter the reservoir area. The metering diaphragm is responsible for regulating the correct amount of fuel coming into the inlet area of the carburettor. If you suspect you have a blockage, the best cause of action is to strip down the carburettor and blow down the fuel veins with an air line or air blower. Eventually the blockage can cause a complete stoppage of fuel going into the engine, therefore causing it bog down and stop. Even the smallest piece of debris that gets past the fuel filter can cause issues the further down the veins it manages to travel, as the veins get smaller and smaller in size.

WEED EATER DIES WHEN THROTTLED FREE

However when the free flow of fuel is interrupted by debris or dirt in the veins, it can begin to cause problems. In this diagram you can see the free flow of fuel in these veins that work their way right around the carburettor and up into the venturi. If you take look at the valve when rigid it reduces the pumping efficiency of the fuel available for the engine as it doesn't have the same degree of movement. When diaphragms age or are made from a substandard materials they can go stiff and rigid. On the valve there is an opening and closing motion that allows the right amount of fuel to come through so that the venturi can be filled with the fuel air mixture. Problems with the fuel pump diaphragm can also occur when the diaphragm ages or when a substandard diaphragm is used. The same effect occurs with a damaged cap. If this happens there'll be excess fuel spilling out and also air will be drawn into the carburettor where there should be just fuel. If the cap becomes loose or the screw holding it in place has become loose it can cause a gap. Fuel Pump Diaphragmīefore checking the fuel pump diaphragm itself, which is inside the carburettor, first check the cap that keeps the diaphragm in place. What can sometimes happen is that the gasket on either side of the manifold can degrade or become damaged in some way, and despite the fact that everything's fixed together tight, if this gasket is damaged then air can be drawn in once again and unbalance the air to fuel ratio. However let's say that the retaining bolt is nice and tight and we've got everything working as it should with the carburettor. Check firstly to see if it's loose and if it is simply tighten the bolt.

The inlet manifold sits between the carburettor and the engine and acts as a spacer between the two.

WEED EATER DIES WHEN THROTTLED FULL

If you have air coming into the carburettor unnecessarily that will cause the engine to bog down, and while there may be enough fuel for idling speed there won't be for full revs.

Because the engines draw in fuel, they will also suck air in through any rupture in the pipe, and therefore affect the fuel to air ratio coming out of the carburettor and into the engine. The next step is to check the external parts of the fuel pipe.

Weed eater dies when throttled