My prime bulb looses pressure and first start is hard. I have to remove fuel line from filter and cover with thumb prime re install then first start takes time.
Does the engine run fine after it starts? Most common problem with primer bulb losing prime is an air leak in the fuel line or primer bulb. Air leaks don't always leak fuel. If there is an air leak between the primer bulb and gas tank there is no pressure, only vacuum. If it is not a major leak it might not leak without pressure but it will allow air to enter the fuel line. If it is a very minor air leak it could allow air to replace the liquid in the fuel line over time, but so little air once it is primer again that the fuel pump can over come it with volume of fuel.
Primer bulbs do not stay firm, as they are when initially pumped up, after the engine is running. There are check valves in the primer bulb that hold pressure in the primer bulb and throughout the fuel line to the engine. Once the engine starts the fuel pump creates vacuum drawing fuel into the engine diminishing this pressure and releasing the check valves. At this point the primer bulb is just another segment of fuel hose allowing fuel to pass through it as the fuel pump demands. The primer bulb functions much better when the outlet side is higher than the inlet side. This position makes it easier for the check valves in the primer bulb to seat and release as needed. If the primer bulb is functioning properly and is positioned with the outlet side higher than the inlet it should not be necessary to cover the end of the fuel hose with your thumb to get it to prime.
If the engine is hard to start after being fully primed there could be a problem with the fuel system on the engine. Some engines are hard to prime once air has entered the system, especially fuel injected models.
Dec 19, 2014 |