RC_KAOS
05-05-2006, 03:30 AM
Sometimes, a nitro engine will play mind games with you, and that can make your nitro experience a bad one. And the more frustrated you get when your engine isn’t running properly, the worse the situation will get. You may get to the point at which you think you’ll never get that engine running, and that’s why we’re here. These 5 engine problems tweaked my noodle a few times, and after a lot of thinking and a few choice words, I solved them. Engines are relatively simple, and only a limited number of things can go wrong. With these 5 problems solved, you shouldn’t have any trouble getting your engine to run.
1. ENGINE DOESN'T START
If your engine ran fine and now doesn’t even start, chances are, your glow plug is fouled or your Ni-starter has lost its charge. I grab the Ni-starter and stick a plug that I know is good into the end of the starter to see whether it glows properly. If it doesn’t, I know I have to charge or replace the starter battery. If that plug glows, I know that the one in my engine is shot. Your engine may not start after it has been running; in this case, the engine might be too hot to ignite the fuel entering the combustion chamber because of the temporary loss of compression and the fuel vaporizing in the carb. Let the engine cool for a while before you try to restart it.
2. ENGINE IDLES ERRATICALLY
If you’ve had to adjust the low-speed needle and the idle screw a million times, you probably have an air leak. It may be in the engine or the fuel system. Check your empty fuel tank by attaching fuel tubing to the pressure fitting and to the fuel fitting and then submerging it in water. Now pinch one of the fuel lines to pressurize the tank with air, and then blow into the other line. Do you see air bubbles coming out of the tank? If you do, identify where they’re coming from and either replace the tank or seal the leak with silicone. The fuel tubing itself can leak, and finding a hole in a piece of fuel tubing can be a pain, so replace the tubing. A fuel filter may also leak air; remove the filter from your vehicle and make sure that the parts are screwed together tightly and that the O-ring is intact. Last, but not least, your air leak may be somewhere in the engine. Instead of trying to find out where the leak is, just take the engine apart and seal every joint with oxygen-safe gasket sealant. Seal the backplate, the carb and all the joints on the high-speed needle. Check all the O-rings and replace any that look worn.
3. ENGINE RUNS ON THE STARTER BOX BUT DIES WHEN THE VEHICLE HITS THE GROUND OR WHEN YOU HIT THE BRAKES
You have a problem with your clutch. Some part of it is hanging up and causing the engine to spin the cutch bell at idle when it is not making a lot of power. It has enough power to turn the wheels when they are off the ground, but as soon as you stop them from turning in any way, the engine dies. Try rotating the clutch bell while the engine is off and the brake is disengaged. If it doesn’t turn freely, you have a problem. Pull the engine out of your vehicle, disassemble it and inspect every part of the clutch assembly. As you take parts off the engine, check to make sure that they are not broken or worn. Replace parts that you think should be replaced, but if everything checks out, see whether the clutch-bell bearings rotate freely. If the clutch bell doesn’t rotate, replace the bearings. Before you reassemble the clutch, lightly scuff the clutch shoes and the clutch bell with fine sandpaper and clean them with motor spray.
4. ENGINE BOGS DURING THE TRANSITION FROM IDLE TO FULL THROTTLE
First, check the low-speed needle to see whether it’s adjusted properly. Drive the vehicle around for a few seconds to clean out the engine, and then bring the vehicle over and pinch the fuel tubing while the engine is at idle. After a second or two, engine rpm should slowly rise and the engine should shut down. If the engine dies right away, your low-speed needle is set too lean, and if it takes longer than a second or two do anything, it’s set too rich. A setting that’s too rich or too lean will make the engine bog slightly when you get on the throttle. If altering the needle setting doesn’t solve the problem, use a “hotter” glow plug. The fuel may be cooling your existing plug and making it hard for it to ignite the fuel in the combustion chamber
5. ENGINE SUDDENLY LOSES POWER
Chances are, your air filter is too dirty or your tuned pipe is clogged. If you have either of these problems, you can lean your high-speed needle all you want and your engine’s performance won’t improve because there’s a lack of air or exhaust flow through it. Clean your air filter, relube it with any air-filter lube and you’ll be good to go. If your exhaust is clogged, you’ll have to remove the exhaust pipe and clean it. If your stinger is clogged, pick out the debris while its end is facing downwards so that the debris falls out; if it’s clogged inside, try blowing the debris out with compressed air. Blow the air into the stinger so that the debris can easily flow out through the inlet side of the pipe.
1. ENGINE DOESN'T START
If your engine ran fine and now doesn’t even start, chances are, your glow plug is fouled or your Ni-starter has lost its charge. I grab the Ni-starter and stick a plug that I know is good into the end of the starter to see whether it glows properly. If it doesn’t, I know I have to charge or replace the starter battery. If that plug glows, I know that the one in my engine is shot. Your engine may not start after it has been running; in this case, the engine might be too hot to ignite the fuel entering the combustion chamber because of the temporary loss of compression and the fuel vaporizing in the carb. Let the engine cool for a while before you try to restart it.
2. ENGINE IDLES ERRATICALLY
If you’ve had to adjust the low-speed needle and the idle screw a million times, you probably have an air leak. It may be in the engine or the fuel system. Check your empty fuel tank by attaching fuel tubing to the pressure fitting and to the fuel fitting and then submerging it in water. Now pinch one of the fuel lines to pressurize the tank with air, and then blow into the other line. Do you see air bubbles coming out of the tank? If you do, identify where they’re coming from and either replace the tank or seal the leak with silicone. The fuel tubing itself can leak, and finding a hole in a piece of fuel tubing can be a pain, so replace the tubing. A fuel filter may also leak air; remove the filter from your vehicle and make sure that the parts are screwed together tightly and that the O-ring is intact. Last, but not least, your air leak may be somewhere in the engine. Instead of trying to find out where the leak is, just take the engine apart and seal every joint with oxygen-safe gasket sealant. Seal the backplate, the carb and all the joints on the high-speed needle. Check all the O-rings and replace any that look worn.
3. ENGINE RUNS ON THE STARTER BOX BUT DIES WHEN THE VEHICLE HITS THE GROUND OR WHEN YOU HIT THE BRAKES
You have a problem with your clutch. Some part of it is hanging up and causing the engine to spin the cutch bell at idle when it is not making a lot of power. It has enough power to turn the wheels when they are off the ground, but as soon as you stop them from turning in any way, the engine dies. Try rotating the clutch bell while the engine is off and the brake is disengaged. If it doesn’t turn freely, you have a problem. Pull the engine out of your vehicle, disassemble it and inspect every part of the clutch assembly. As you take parts off the engine, check to make sure that they are not broken or worn. Replace parts that you think should be replaced, but if everything checks out, see whether the clutch-bell bearings rotate freely. If the clutch bell doesn’t rotate, replace the bearings. Before you reassemble the clutch, lightly scuff the clutch shoes and the clutch bell with fine sandpaper and clean them with motor spray.
4. ENGINE BOGS DURING THE TRANSITION FROM IDLE TO FULL THROTTLE
First, check the low-speed needle to see whether it’s adjusted properly. Drive the vehicle around for a few seconds to clean out the engine, and then bring the vehicle over and pinch the fuel tubing while the engine is at idle. After a second or two, engine rpm should slowly rise and the engine should shut down. If the engine dies right away, your low-speed needle is set too lean, and if it takes longer than a second or two do anything, it’s set too rich. A setting that’s too rich or too lean will make the engine bog slightly when you get on the throttle. If altering the needle setting doesn’t solve the problem, use a “hotter” glow plug. The fuel may be cooling your existing plug and making it hard for it to ignite the fuel in the combustion chamber
5. ENGINE SUDDENLY LOSES POWER
Chances are, your air filter is too dirty or your tuned pipe is clogged. If you have either of these problems, you can lean your high-speed needle all you want and your engine’s performance won’t improve because there’s a lack of air or exhaust flow through it. Clean your air filter, relube it with any air-filter lube and you’ll be good to go. If your exhaust is clogged, you’ll have to remove the exhaust pipe and clean it. If your stinger is clogged, pick out the debris while its end is facing downwards so that the debris falls out; if it’s clogged inside, try blowing the debris out with compressed air. Blow the air into the stinger so that the debris can easily flow out through the inlet side of the pipe.