Tuning a Stock Zenoah engine


Zenoah G230/G260/G290 RC (H) 1.1/2 turns (L) 1.1/4 turns (these are stock settings)
 Modified engines usually require more fuel and have the settings at 1 on the High and 2 on the Low as a starting point, Altitude, weather, pipe and other variables can require different settings. Settings may also be the same for the CY / Fuelie engines.

these are the factory settings on the ZENOAH engines. They are set according to local conditions. This is depending on the air filter, exhaust and climate conditions. Use the above settings as a starting guide line and depending on what your engine set up is, you will probably have to make some slight adjustments.

As I said earlier, the standard settings are just a guide line and most carbs have to be adjusted, If you feel that your no-load (L) or your full load (H) screws are completely mis adjusted, then carefully turn the mixture screws clockwise till they stop. Then turning them counter-clockwise follow the settings that are listed above.


Always make sure the throttle is in the closed position. Now apply the choke which is on the carb on the Zenoah engine or on the air filter. Press the primer pump located on the carb until the pump is full of fuel, this you will be able to see. Pull the handle until you hear the engine try to start, this usually takes 2-4 pulls. When you reach this stage, open the choke and give another couple of pulls. This should start your engine.

Make sure that there is fuel in your primer cap and that the choke is open, then pull cord.

BEFORE YOU START              

Before you start to tune your engine there are a couple of basic things that you should check first. Firstly make sure that your spark plug is in good condition. You do this by simply un-screwing it out of the cylinder and checking it, if the electrode looks too oiled up then change it as it will make things a lot easier. Most plugs come with the gap pre set but it wont hurt to check to make sure its right. Secondly make sure you have enough fuel as it soon runs low with all that testing and reeving, also make sure that your filter is on nice and secure with no possibility of air leaks. And lastly make sure your batteries are nice and charged. Let us begin!

This is based on the assumption that your car starts but is not running right. Firstly make sure that you have the mixture settings set to the factory settings. This is quite important at this stage. Then turn-in the idle screw in till it bites on the spring that it is set in, then give it one more full turn. Doing this should keep your revs up once you have pulled the starter and got her going. Before you pull the starter make sure your radio is on and working. Pull the starter and after a couple of pulls she should start, if not then you may have a problem which we will cover in our trouble shooter section. While the car is running you will be able to tell if the engine is reving to high just by listening to it. If it is then turn the idle screw out slightly (counter-clock wise), only slightly as the engine is still cold and does need to warm up, it is pointless trying to tune a cold engine. Drive the engine until it reaches working temperature. If you notice that the engine decelerates during acceleration, then your engine is running too lean. To rectify this the no load screw L should be turned counter-clockwise. Imagine the screw being a clock, then your adjustments have to be made in 5 minute turns, in other words very small movements. If the engine revs up slowly and runs rough under clouds of smoke, this means you are probably running with an over rich mixture. In this case you should turn the no load screw in clockwise by 5 mins at a time until you have rectified the problem. Run the car repeatedly making minor adjustments until you are happy with the way it is performing.

For vehicles : In order to adjust the maximum range of speed, lift the rear wheels and rev the engine shortly at maximum revs. Now you can adjust the Full load screw H to the left to richen the mixture or to the right  to make it leaner. You will hear the engine reaching its peak revs and you can also notice when it starts to loose the peak. The best way to tune your car is to run it on a track or field and make your adjustments after each run. Remember to make very slight adjustments at a time, this way you will see your improvements a lot better.
For Aircraft: Tune for highest rpm on the ground and then richen the high needle a little bit, since the rpms will go up when flying.


When tuning your engine, after every run make sure you check the bubble on the carb. If this is empty after testing then this means your engine is too hot and running too lean. What you should be looking for is a full bubble or nearly full at least.

You should also be aware of your engine if it smokes to much, this means it is running too rich and is getting too much fuel. To adjust this turn your L screw in by 5 mins, remember imagine that the screw is the face of a clock, small adjustments is all you need.

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