Nitro RC Carburetor: How to Fix Air Leaks in RC Nitro Engines

Troubleshooting is important for your RC car so that you can notice earlier some small problems that might affect your RC car in the long run. Unfortunately, several issues can easily appear in the functioning of your engine. One such issue is an air leak that can affect your RC car engine.

As you know, nitro engines use a glow plug in order to ignite fuel. The fuel/air mixture must pass through the intake passage and crankcase before heading for the combustion chamber. This problem will appear here: air can leak in the crankcase either from the carburetor intake and can cause a lean air/fuel mix and, consequently, engine overheating.

In order to fix this air leak, you will need some supplies: a small screwdriver set, engine degreaser, silicone sealant, cotton swabs, and a small plastic tie fastener. This task is not difficult, but you need to be very careful and follow the steps accordingly.

First of all, you need to remove the engine from the RC car, according to your car’s assembly manual. This process implies disconnecting the throttle linkage, removing the screws and disconnecting the fuel line. Next, you need to remove the air filter from the engine’s carburetor. The filter is small, circular and it is made out of foam and rubber.

The bolt which secures the carburetor from the engine needs to be loosened. This is located between the carburetor and an angled portion of the engine. Use a small screwdriver or an appropriate size Allen wrench to do that.

Now that the carburetor is loose, lift it up and set it to the side. You will find four bolts which secure the crankcase cover. You need to loosen them up, using a screwdriver or an Allen wrench. Remove the cover and clean the sealing points with the degreaser. The cleaning operation continued with the wiping off of the carburetor and crankcase cover. Use a clean towel for that.

Silicone sealant is extremely important at this point. Apply a small amount of sealant around the neck of the carburetor. This helps with the air leaks. Now you can put the carburetor back on to the engine’s intake and tighten the punch bolt. Apply another coat of silicone sealant around the interior surface of the crankcase cover.

Turn the crankshaft until the piston’s connecting rod is in the upmost position inside the crankcase. It is located inside it, and you can easily see it if the crankcase cover is removed.

Reinstall the cover on the rear of the crankcase, but be careful not to remove or smear the silicone when you put it back. Place the screws for the cover of the crankcase.

If there’s some silicone residue left on the carburetor or cover, you can wipe it off with a clean cotton swab. The sealing process now continues with both ends of the pinch screw. Seal them well with small amounts of sealant. Afterward, you can place and secure a plastic tie fastener around the throttle arm boot, where the arm boot meets the metal body of the carburetor.

Cut the excess tie fastener and let the silicone and engine dry for 24 hours. Afterward, you can reinstall the filter to the carburetor and put the engine back into the RC car.


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