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How To Install Rotec TBI and Regulator

Applies To Models
  • Rotec TBI-40-S: (Standard Spigot style mount to suit Jabiru, Rotec and Rotax)
  • Rotec TBI-40-3: (Aviation flange #3 i.e. smaller aircraft engines like 0-235)
  • Rotec TBI-40-4: (Larger aircraft engine 0-320 etc)
  • Rotec TBI-48-4/5: For large engines 0360 and above
To Get Started Just Follow These Basic Steps/Tips:
  • Mount TBI unit on your engine, make sure there no air leaks between the TBI flange and the engine inlet manifold. Use a good quality air filtration system complete with exhaust heated carburettor anti icing system. Dirty air can impede the mechanical action of the slide throttle.
  • The location of the fuel regulator MUST be at the same HORIZONTAL level as the TBI fuel fitting or slightly above. The regulator should be located at a distance no farther than 6ā€ from the air intake from the TBI unit. Closer would be better. The shorter this distance the less effect gravity will have on the regulator when pulling Gā€™s. In some installations it is possible to mount the regulator directly to the TBI fuel fitting using an elbow fitting. This would be ideal.

  • (VERY IMPORTANT) Connect the pressure ballancing hose between the air intake and the regulator.

  • Connect the fuel line to TBI unit as per any typical carburettor. The fuel pressure from your normal engine and boost pumps will be suitable to use with the TBI unit. A range of .5-6 psi of fuel PX will be good.
  • For convenience the fuel fitting can be swapped from one side to the other.
  • Note the TBI unit has a built in finger fuel strainer this is our last chance filter only and should be serviced every 100hrs. Blow out or clear as necessary.
  • The airframe MUST have it own fuel filters, and not rely solely on the last chance filter in the TBI unit!
  • The TBI unit will need to have typical Bowden cables connected to it to control both slide throttle and mixture lever. WARNING! Do not hang heavy unsupported cables on the mixture lever, this can results in the damage or failure off the mixture lever and or base of the spray bar
  • The mixture lever can be re positioned on its ratchet base.
  • The fuel fitting threads on the TBI regulator are 1/8ā€ NPT. Warning be careful not to accidently see debris enter the fuel system as a result of using sealant compounds and or tapes BE VERY CAREFUL!!!!
  • To avoid vapour lock all fuel lines should be shrouded in typical fireproofing hose. AVGAS is the preferred fuel as it is far less prone to suffering from vapour lock. Auto fuels vapour lock easier and extra precautions need to be taken when using this fuel type.
  • Keeping COOL all fuel related items such as the TBI regulator, fuel pumps. and fuel lines etc is highly recommended. Again this is to avoid any possibility of unwanted vapour lock! Air blasting these items can greatly reduce there temperature.
  • Set idle mixture screw for best Idle and pick up. The TBI unit does not have an accelerator pump so rapid use of the throttle slide should be avoided. Setting the idle mixture screw a little on the richer side can aid pick up and is recommended.
  • The slide throttle stop should be set for best idle speed. A combination of both the idle mixture screw and the throttle stop will result in best idle performance.
  • A full open slide throttle stop should be set on the throttle quadrant so as to avoid pulling on the roll pin that secures the slide lever to the slide throttle tongue.

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EXTRA NOTES: 15-03-2010

  • The full rich position should be set at a point which results in an 80 degree F drop from maximum EGT. This will almost certainly be at a lever position before the TBI rich full stop.
  • The use of a return line is not needed even if using Auto gas. Just keep all the fuel lines fire sleeved and keep components as cool as possible.
  • The full LEAN position is when all the tiny holes along the spray bar are at 12:00 or pointing straight up.
  • The full RICH position is when the holes are position to the side or facing the side wall of the TBI throat.
  • The TBI regulator should be located as close as to and as central as possible to the horizontal centre line of the TBI throat.
  • The idle mixture screw is located on the side of the TBI housing and can be accessed using a 5mm ball Allen hex key.
  • The mixture is factory set at 3/4 of a turn from being full closed. This should get you started but fine adjustment will be required to set the perfect idle mixture. DO NOT RAM THE NEEDLE HARD INTO THE SEAT IT WILL JAM AND BREAK OFF!!!!
  • The ENGINE WILL NOT LEAN CUT while the engine is idling. This is because the idle fuel deliver jet is separate from the main fuel spray bar. So leaning the main spray bar (ie holes facing forward) will have no affect on the engine and it will continue to idle. To lean cut the engine you must first go to full lean and then raise the RPM until the engine quits. Or just switch of the mags like I do!
  • The inclusion of a cockpit mounted TBI primer lever is highly recommended as it could be used to save your bacon should vapour lock or some other fuel starvation anomaly ever occur. In the case of vapour lock (very unlikely) you would simply jab or hold the primer lever on so as maximum fuel would flow through the regulator and quickly flush out the vapour lock.

  • It is veryimportant to connect the pressure ballancing hose for uniform and optimum operation of the TBI

Setting Up The Rotec TBI Cable. 2 Videos on the arrow to go back to the top menu back2top