Carburettor adjustments for Moster 185
Moster series engines
A simple and fast control. You don’t have any experience or affinity with the motors? Don’t worry, follow step by step what we tell you in this chapter.
When you receive the motor, it has already been tested for 15 minutes in the factory’s test-bench, verifying the operation, the assembling and the optimal carburetor setting. These regulations guarantee a perfect stability of the motor, the operating temperature and the correct lubrication to every organs of the motor.
Moster 185 (all versions)
from 1/4 to 1/3 of turn
Screw H from 1+1/8 to 1+1/4 of turn (warranty sticker lock). The break-up of the warranty sticker lock automatically void the warranty.
Whenever you choose to verify the carburetor settings, proceed in this way. Remember: a strong pressure (tightening) on these screws can irremediably damage the carburetor.
Following these guidelines, you can perform a simple check of the carburetion, but only once the engine has been safely alight and heated for few minutes.
• The motor has to maintain a constant idle and must not to have the tendency to go off or to flood.
• When you pull the throttle fastly from the idle rpm, the motor immediately has to react without going off or suffering lacks of power.
• Simulating a cruise flight (about 1/4 or 1/3 of throttle), the motor have to react with a regular thrust, smooth and not with hiccups or power jumps.
• At full throttle, the thrust has to be constant and the max speed between 8.000- 8.600 RPM.
Attention: if the carburetion of the motor (the quantity of gasoline that arrives to the motor) is poor, therefore the opening of the screw is lower compared to the indications of the chart, breakups as seizures, overheatings, fusion of the piston, precocious wear of the components will probably occur.
Problems to the motor due to a lack of oil in the gasoline or a wrong mixture oil/gasoline, impurity in the fuel or a incorrect carburetion, immediately void the warranty (See chapter warranty 11.3).
A check of the carburetion can be made, verifying the color of the spark-plug electrode. A first control can be done, at the end of the of break-in period, in the following way:
• If the electrode is brown, the carburetion is correct.
• If the electrode is grey or light, the carburetion is poor and you have to
immediately seek the cause, with the help of an authorized dealer/instructor.
• If the electrode is dark brown or black, the carburetion is rich.
Watch out for the regulation of the screw H, because if this is too closed compared to indicated values, you could have damages to the motor. No damage will occur if the carburetion of the screw H is too opened (rich). If you have doubts, is always better to have a rich carburetion for the screw H.
Start the engine. If engine is still cold give it several minutes on 4000-5000rpm, then bring up the rams to 6000-7000 for 3-40 seconds, after that drop the throttle. Look how engine is going to react, this is important. Revs should drop to 2000(+/- 5%). Engine should work correctly from 3000 to 8000 without any jumps in revs. After 5000 rpm there should be no major vibrations.
Usually when we get new engines from Vittorazi we adjust the L Screw on the carb during the break in period. Vittorazi send engines from the factory adjusted for Italian conditions. You probably need to turn L screw clockwise 5°.
Start the engine. If engine is still cold give it several minutes on 4000-5000rpm, then bring up the rams to 6000-7000 for 3-40 seconds, after that drop the throttle. Look how engine is going to react, this is important. It should switch to idle, revs should drop to 2500-2800 stay there for 10 seconds and then drop to 2000(+/- 5%). If this doesn’t happen and revs drop strait to 1200-1800 you should:
Shut the engine.
Turn L screw clockwise 5°.
Start the engine, bring the rpms to 6000-7000, hold for 30-40 seconds, release the throttle.
Look at how situation is changing.
Adjust the L screw if needed, repeat until desired result achieved.
With correctly adjusted carburettor start of the engine should be smooth, fast and easy.