How to Free a Stuck Valve on an Intex 18 HP Lawn Mower Engine

Find the rectangular valve cover situated on the left side of the Intex engine. Remove the bolts on the cover with a socket wrench, then pry the cover off with your hands.

Loosen the screw at the center of the bolt that lies on the top rocker arm using a Torx screwdriver. Both rocker arms are revealed after removing the valve cover, although you will need to focus on the top rocker initially.

Slide a feeler gauge under the left side of the engine's top rocker arm. Loosen the rocker arm's bolt with a socket wrench if the feeler gauge will not fit under the arm. The feeler gauge should slide under the arm and stay in place under the arm after being inserted. Tighten the bolt back up slightly if the gauge is too loose under the rocker arm.

Re-tighten the top rocker arm's Torx screw using the Torx screwdriver.

Repeat the same adjustment procedure on the bottom rocker arm. This will adjust the air intake into the machine properly and free the stuck valve.

Secure the valve cover onto the Intex engine using its removed bolts and your socket wrench.