MVVS 40 IFS User Manual

Operating instructions

MVVS 40 IFS No.: 3095I

MVVS 40 IFS SP No.: 3095SP

Before using the engine, carefully read these instructions

Congratulations on choosing the gas engine MVVS 40ccm.
MVVS 40 IFS has been designed and manufactured for propeller-powered radio-controlled model planes. It is able to
meet all of your expectations of an acrobatic racing engine.

MVVS 40ccm

Bore

Weight of complete e ngine
without ignition*
Weight of ignition unit
RpM range

* The value in the table above stands for the weight of a completely assembled engine, including the spark plug,
carburetor, drive washer and prop screws.
** Power output varies with the exhaust used. The value given in the table stands for the maximum available power
output.

Engine’s dimensions

Technical specifications

38 mm

1457 g

200 g

1400 – 9000

A

40 IFS 182 118 60 84 70
F

40 IFS 41 5,3 M10x1 10 45

Stroke

Fuel

Lubrication

mm B mm C mm D mm E mm

mm G mm H mm I mm J mm

Unleaded 95-octane fuel

Oil with petrol in mixture 1:40

35.2 mm

Safety precautions

1) Never use the engine for any manned vehicles.

2) When operating model planes, always follow the rules and laws in effect in your country.

3) The manufacturer declines all responsibility for all damages arising from the operation of models and other
appliances droved by MVVS engine.

4) Always use original spare parts.

Version 1.1

5) Never tamper with the engine construction.

6) Before each flight check that all the propeller screws are ti ghtened up and in good condition. If you use a
spinner, check t hat it is tightened up, too. When mounting the spinner always follow the assembly
instructions.

7) Before each flight check that all the propeller screws are ti ghtened up and in good condition. If you use a
spinner, check t hat it is tightened up, too. When mounting the spinner always follow the assembly
instructions.

8) Periodically check that the engine is firmly fixed to the engine mounts. Never start a loose engine!

9) Always use a balanced propeller! Always replace the propeller when damaged!

10) Make sure that no part of your body intersects the plane of the spinning propeller.

11) Always wear close-fitting, well-fastened clothes when starting or operating the running engine. Ne ver wear
loosely hanging clothes (ties, scarf, etc.).

12) Never try to stop the engine by any part of your body.

13) Always stop the engine either by turning off the ignition switch or by completely closing the carburetor
throttle valve.

14) Before starting the engine always make sure that the model is safely fixed in place and cannot start moving.

15) Fuel is combustible and therefore must be kept in an enclosed container at a safe distance from the engine
when it is running.

16) When preparing fuel carefully follow the manufacturer’s or dealer’s instructions.

17) Small objects must be kept at a safe distance from the engine when it is running. Never throw any objects
towards the spinning propeller.

18) Be careful in choosing the location where you wish to start the engine. Avoid dusty or sandy areas.

19) Start the engine in well-ventilated areas only. Never start the engine indoors.

20) When starting the engine make sure that bystanders, especially children, are at a safe distance of at least 10
meters.

21) The engine power output makes it possible to fly big models. Mal-operation of such models may cause
serious damage. Start using the MVV S 40 in model planes only after you have mastered operating smaller
models.

It is usually the case that propellers of the same dimensions coming from different manufacturers are not the same.
Oftentimes not even propellers of the same dimensions produced by a same manufacturer are not the same. The en gine
power is best utilized when the propeller dynamics curve and engine power curve ( revolutions / power output) intersect
in the area of t he en gine top power output. Unfortunately, no propeller manufacturer provides t his information. Engine
power output is also a variable quality. It depends above all on the silencer used and can considerably vary. The situation
is further complicated by environmental parameters (temperature and atmospheric pressure in particular): low
temperature and high pressure increase propellers’ input requirements by 20% in comparison with input at hot weather.

MVVS 40 has been designed to generate maximum power at 7000 RpM, according to the type of exhaust used. If you
wish to utilize the maximum power output, choose a propeller which allows the engine to reach these revolutions, or
slightly lower revolutions (given the unloading of the propeller depending on the speed of flight) on the ground.
We do not recommend to use propellers with which the engine reaches more than 9000 RpM and les s than 6000 RpM
on the ground.

Always use unleaded 95-octane petrol mixed in the proportion 40 volume units of petrol to 1 unit of Mobil R acing 2T oil.
If necessary, quality brand-name synthetic oil intended for racing two-stroke engines can be used too.
Mix it in the proportion 30:1.
Never use inexpensive oil developed for garden appliances or synthetic oils intended for the operation of methanol model
engines. The manufacturer declines all responsibility for all engine damages arising from the use of low-quality fuel.
Store fuel in containers designed for this purpose. Do not use mixed fuel older than 90 days.

Since air is used to cool the engine, sufficient air circulation under the cowl must be ensured. Never forget about a hot air
outlet – which must be bigger than the intake. Gas engines heat up to a much greater degree than methanol ones!

Do not forget that the engine needs oxygen from the air to be able to operate. Therefore ensure access of air to the engine
intake as well. Caution: intake of warm air from beneath the cowl may cut the engine power output.

Caution!
When mounting the engine in the model use seals to protect all openings and prevent the pollution of the engine’s
inside with sawdust, residual abrasives etc.

Selecting a suitable propeller

Suggested propeller dimensions:

MVVS 40:
18x8, 18x10, 20x8, 20x10, 20x12,21x8, 21x10

Fuel

Assembly

Exhaust

Use only factory-made exhausts pipes designed for this type of engine, preferably brand-name MVVS engines with
which you also get the power output guaranteed.
The manufacturer declines all responsibility for all engine damages arising from the use of improper exhaust systems.
When mounting the exhaust follow the manufacturer’s instructions. Make sure to secure sufficient cooling of the exhaust.

3271 compact, medium level of power output
3268 tuned pipe, with adaptor 3269 provides the highest power output, with the flat torque curve, useful for the

3268

3271 3269

model planes

Carburetor adjustment

Basic setting:

(Minutes refer to hands of a clock)

adjusting needle ( L ) for low RpM range 1turn and 45 minutes
adjusting needle ( H ) for high RpM range 1 turn and 45 minutes

Walbro WT 561

Choke

Pressure pulse inlet

The new engine comes adjusted to the basic setting.

After the engine has been run in, adjust it following the instructions below:

- start the engine and warm it up

- let the engine run at idle speed for approx. 5 se conds

H needle adjusting screw

L needle adjusting screw

for WT 561

Lever - throttle