How to Repair a Weed Eater Engine

Set the trimmer on a flat and stable surface, preferably over some laid out newspaper or old cloths to absorb spills. Drain the gas using a small gauge hose inserted into the tank and allow the engine to fully drain into a plastic pan. Don’t discard the gas -- you can always pour it back in when you’re done. With tank empty, locate the engine’s holding screws on the sides of the trimmer that anchor the engine to the base. Use an appropriately sized Allen wrench to unseat all four to six screws and set them aside.

Slide the carburetor off with a gentle yet firm twisting motion – too much force and you’ll risk cracking the throttle yoke, a repair you’d rather not have to deal with. The first set of screws mounted the filter and the choke plate, so set those two components aside and out of the way while you concentrate solely on the engine.

Lay out a large white cloth, a surface where small and delicate parts can rest. White makes them more visible and reduces the risk of losing any important pieces. Of note: lay the parts out in the same order as they’re removed so you can backtrack and reassemble the unit with relative ease. Unscrew the small Phillips head screws in the idle settings – the longest one is the High Idle screw, the shorter is the Low Idle. Rinse each screw with brake cleaner to remove built up crud.

Replace the spring with the new spring from the replacement kit. If the engine won’t start, chances are this little component is the culprit. Look over the pieces as you disassemble the unit; any that look worn, replace them with new parts taken from the carburetor kit. Salvage old parts by cleaning them first and keep the kit components as spares.

Look down into the top of the needle valve and you’ll find a small filter screen. Pop out the old screen, discard it and replace with a new one. The little screens are prone to quick buildup that hinder fuel flow, so toss it in favor of the new one. Reassemble the unit once the parts are replaced by backtracking over the parts, starting with the most recent part first. Funnel gas back into the unit and make sure oil levels are acceptable and start the trimmer.