Ten Tips to Get That Engine Running

Mar 11, 2011 23 Comments by

Nitro engines aren’t a plug and play deal like brushless power and because of that, time needs to be spent tuning and trouble shooting them in order to enjoy your time with them. These engines are very simple machines and don’t require much to run. If it’s getting air, fuel and spark, the engine will fire. But things don’t always go smoothly and there will be times where you have to figure out what the engine is asking for in order for it to run correctly. These 10 tips are here to help you end the frustration and start up the enjoyment.

Engine won’t start

Check to make sure that your glow starter is fully charged. You can quickly check by taking a new glow plug and plugging it into the end of the starter. If it glows, then it’s charged and the problem is somewhere else. If it doesn’t glow, then need to charge it or replace the battery and you should be good to go. If the glow starter isn’t your problem then you might have a bad glow plug. Remove the glow plug from the engine and test it by plugging it into the glow starter. If all else fails, check to make sure you have fuel in the tank. Yes, that’s something that people over look.

Engine starts but stalls right away

OK, so you fire up your engine and it’s running fine then the second you pull the glow starter off the heat sink head, the engine dies. This could be a sign of a glow starter that isn’t fully charged or a glow plug that is one the edge of going bad. Start by putting your glow starter on charge or replacing the battery and try it again. If the problem still happens, replace your glow plug.

Engine runs on starter box but stops when vehicle hits the ground or when you tap the brake

This is happening because there is something hanging up on the clutch and not allowing it to disengage from the drivetrain. So the second you stop the drivetrain in any way, the engine will die. The same thing happens when you hit the flywheel to shut the engine down. Remove the engine from the chassis and spin the clutch bell to see if there’s any drag or if it’s locked all together. If there’s drag on the clutch bell, then you may have a clutch shoe or clutch spring hanging up. If the clutch bell is locked up all together, you have a bad clutch bell bearing. Replace both bearings even if only one clutch bearing is bad because chances are that the other one is on the same path.

Engine stalls when you hit the throttle

This is a sign that your high-speed needle is set to lean and the engine is starving for fuel. Simply richen the high speed needle a quarter turn and make fine adjustments from there to get it set properly.

Engine looses power when you hit full throttle

This is a sign that your high-speed needle is set too rich. A sign is that the vehicle isn’t as fast as it was when the engine had a proper tune and you’ll see lots of smoke coming out of the pipe. Lean the high speed needle until your engine is running properly and at the correct temperature.

Engine struggles to move vehicle

Two things can be going on here. Your low-speed needle is set to rich or two lean. If you get on the throttle and your engine wants to die the second you touch it, your low speed needle is set to lean. If your engine is slow to react and stalls, then your low-speed needle is too rich. To check the condition of the tune on the low-speed needle, I like to do the pinch test. Drive the vehicle around if possible to clear it out and bring it over to you and immediately pinch the fuel line. You want the engine to run for a second or two before stalling out. If the engine dies right away, the low-speed is set to lean. If it takes longer, then your low-speed is set too rich. If you can’t get the vehicle to run enough to clear the carburetor out, perform the pinch test to get a general idea of where you’re at.

Engine runs too hot

An overheating engine can be caused by lack of air flow or a carb that is set to lean. Take a look at the body on your vehicle and make sure that there are venting holes in the windshield and behind the cab. Richen up the high-speed needle on the carb. A dirty engine can reduce the cooling capabilities of the engine and cause it to overheat. A tooth brush and some nitro cleaner will do a great job at removing any grime.

Fuel not reaching engine

If you are trying to fire up your engine and you see that the fuel isn’t flowing to the carburetor, you have a clog in the fuel system. You can check the fuel tank by removing the pressure and fuel line from the pipe and engine. Once they are removed, you can blow into the pressure line and look to see if any fuel comes out the other. The fuel should flow with no effort. If it takes a lot of pressure to make the fuel come out or it doesn’t come out at all, the fuel tank is clogged and needs to be replaced.

Engine runs erratically at idle

It can be frustrating when you can get the engine to idle consistently and that’s because of an air leak in the engine or fuel tank. Check the tank for leaks by plugging the exhaust and fuel lines and submerging it in water. While under water, check for air bubbles. Another area where you can find an air leak is in the fuel lines. If you see bubbles flowing inside the fuel line or suspect that is where your air leak is coming from, replace the line. It’s not expensive and needs to be done from time to time anyway. You can also take the engine apart and seal the back plate, carb, and high-speed needle assembly with O2 safe sealant.

Engine won’t turn over

Two things can keep an engine from turning over, too much fuel in the combustion chamber or a seized piston and or crankshaft. If your engine was turning over the suddenly locks up, chances are that you have a hydra lock condition where there’s too much fuel in the combustion chamber. All you have to do to fix it is remove the glow plug and turn the engine over to blow out the excess fuel. If that’s not the problem, then you’ll be replacing parts or an entire engine if you have a seized condition.

What is the ideal engine temperature?

There are a lot of theories out there on what the best operating temperature for your engine. Some look for an engine temp of 230 some may recommend a higher temp. Before running any nitro engine, take a look at the owner’s manual to see if there’s a recommendation there. Ever engine is different and a temp that will work for one engine might not be ideal for another.

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About the author

Simply put, I’m all about nitro. Well, almost. I’m down with electric for crawlers and some indoor racing, but if you really want to get my attention, it better make some smoke and noise. I’m a regular racer and I usually go with 1/8-scale buggy and truggy. When I’m not racing, I am usually fabricating custom parts and even entire vehicles.

23 Responses to “Ten Tips to Get That Engine Running”

  1. member25255 says:

    ENGINE WON’T TURN OVER : could also be caused by the piston being stuck top dead center (often on brand new engine), usally fixed by turning the flywheel with a flathead screwdriver which will move the piston. If piston is stuck horribly you can remove the glow plug first.

    Thanks for the tips Kevin!!!

  2. DAVE LYTLE says:

    I HAVE A NEW DYNIMITE .21 NITRO MOTOR IT IS NEW AND STICKS AT TDC I CAN’T TURN IT OVER EVEN WITH THE PLUG OUT, ON MY STARTER BOX, IT WILL BARELLY TURN OVER PAST TDC WITH A SCREW DRIVER AGAINST THE FLYWHEEL.

  3. roberr says:

    Try taking off the heat sink head and pull out the piston sleeve then put a few drops of oil on it and in the chamber then slowly pull it over.

  4. roberr says:

    The same thing happened to my Baja 33cc

  5. Scott Land says:

    i have an older t maxx. It had been sitting in the garage for about 3 years or so up on the shelf. the other day i had the bug to get it going again. i cleaned out the fuel tank, put in a new glow plug made sure the engine would spin freely. i ran the electric start for about 3 minutes before it started up. after it started up it ran (rather sluggish) around the yard for about 2 minutes. It died on me and now i can`t get it to fire. The motor turns over with the electric start but will not fire. i can hear the compression with the electric start turning. I removed the fuel line from carb and pushed the primer on the tank a few times to make sure fuel was flowing and it was. i tried adjusting the carb with no luck. i`m stumped!!

    • John says:

      I have the same problem…..i have to tap the electric start over and over and then it gets some compression up, then it will fire after probably 5 min……glad to hear someone else is having this problem…not glad for your frustrations of course but now we can work together!!

      • randis says:

        could be poor seal compression cause it went lean and scored piston. you’ll only get fuel seal cold.
        turning over for several minutes means either bad glow battery or plug, you are relying on catalytic compression to get it started.

  6. chris rivera says:

    when I remove my glow the engine stop why

  7. daniel says:

    i trying fire up my .15 motor won’t i put nirto in carb it not make try start but smell burn fums but no fire up how many turn needle supposed be?

  8. Elliot says:

    Hi there I have a nitro car dirt car and it wont start can u help me ?

  9. ADDAM says:

    MY CAR WAS RUNNING FINE THEN I TURNED IT OFF NOW EVERY TIME I PUT THE BUMP STARTER IN AND TRY TO START IT IT MAKES NO SOUND OR NO TRY TO START WHAT MAY THIS BE

  10. randis says:

    you forget a broken con rod, wouldnt turn over, broke the pull start. made my own. can’t beat electric starters, they start any motor, unless you had the head off and might have got it cocked and loses compression. it’s too easy to do. i’ve skinned my fingers yanking on the damn pull starters.
    if you die when you take the glow starter off, its not running hot enough, lean it. or higher nitro, or wrong temp glow plug for your fuel.

  11. randis says:

    adam, what about the clutch nut? had one go, no turn over.

  12. Baz. says:

    Hi there me and a friend recently bought a sledgehammer s50 each and there being a complete pig to set up. Does anyone know they basic needle settings, and ill go from there.

    • Erich Reichert says:

      Not sure where to start with that one Baz but the best place to start is probably with a call to Thunder Tiger.

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