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Primer bulb past its prime? It's time to face the fix. Whether you are a legendary landscaper or a weekend weed whacker, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.
The primer bulb (also known as the purge bulb) is part of your trimmer's carburetor. Its purpose is to prime the engine for starting by pumping fuel into the carburetor. This also removes air from the carburetor, which helps the engine start more quickly and easily.
Over time, the primer bulb may begin to deteriorate or crack. Fortunately, replacing the primer bulb is very easy to do. This article provides step-by-step instructions for removing and installing the primer bulb on an Echo SRM-225 trimmer.
Let's get started.
REMOVING THE PRIMER BULB [top]
1. Remove the air cleaner assembly.
Loosen the thumb screw.
Remove the air cleaner lid.
Remove the air filter.
2. Drain the fuel.
Drain the fuel before servicing the unit.
3. Remove the air cleaner case.
Loosen the (2) bracket retaining screws.
Remove the air cleaner case (along with the bracket and the screws) from the engine.
4. Remove the carburetor.
Use a wrench to loosen the throttle cable adjusting nut.
Disconnect the throttle cable from the throttle body.
Disconnect the (2) fuel lines from the carburetor.
Remove the carburetor from the engine.
Locate and remove the intake insulator gasket. (This gasket is situated between the carburetor and the intake insulator block. Typically, the gasket will fall away from the two components as they are separated. Sometimes, the gasket will remain affixed to either the carburetor or the intake insulator block.)
5. Remove the primer bulb.
Remove the (4) screws from the primer pump cover.
Remove the primer pump cover.
Remove the primer bulb.
INSTALLING THE NEW PRIMER BULB [top] 6. Install the primer bulb.
Install the new primer bulb onto the purge base assembly.
Install the primer pump cover over the primer bulb.
Secure the primer pump cover and the new bulb with the (4) screws.
REASSEMBLING THE UNIT [top] 7. Reconnect the fuel lines to the carburetor.
Remove the gas cap and locate the fuel filter. The filter will be attached to the INCOMING fuel line. Make note of this fuel line for use in the next step.
Plug either one of the carburetor ports with the tip of your finger; depress the primer bulb several times. If the primer bulb softens (deflates) without returning to its original shape; you have plugged (and identified) the incoming port.
If the primer bulb fills with air (hardens) and wont allow further priming; you have plugged (and identified) the RETURN port.
Connect the INCOMING fuel line to the INTAKE port on the carburetor.
Connect the RETURN fuel line to the RETURN port on the carburetor.
8. Reinstall the throttle cable to the carburetor.
Rotate the throttle lever on the carburetor to fully open the throttle.
Thread the throttle cable through the brass connector on the top of the carburetor.
Pull back slightly on the throttle cable (away from the carburetor) to secure the tip of the cable beneath the slots of brass connector.
Press the throttle adjustment nut (on the cable) into the recess on the throttle body.
Use a wrench to secure the secondary throttle nut.
9. Reinstall the carburetor.
Thread the (2) mounting screws through the mounting holes on the air cleaner bracket and the air cleaner case. The bracket should be flush against the interior of the air cleaner case (on the same side as the choke valve).
Thread the screws (protruding from the air cleaner case) through the holes on the carburetor assembly.
Note that there are two small holes on the intake gasket (besides the main intake opening and the two mounting holes). These small holes need to align with the small hole on the insulator block.
Thread the screws through the mounting holes on the intake gasket and slide the gasket flush against the carburetor.
Install the intake assembly (bracket, air cleaner case, carburetor and intake gasket) onto the intake insulator block.
Secure the intake components (bracket, air cleaner case, carburetor and intake gasket) with the screws.
10. Reinstall the air filter.
Install the air filter into the air cleaner case.
11. Reinstall the air filter lid.
Install the air filter lid onto the air cleaner case.
Secure the air filter lid with the thumbscrew.
You don't have to leverage your savings to level your lawns. As you just learned, repairing your own equipment is easy when you follow our step-by-step guides. Not only did you restore trimmer functionality at a fraction of the cost of replacement; you have taken the edge off of future repairs, wherever you may find them.
