MVVS 3007L 80 IRS, 3007SP 80 IRS SP, 3007TS 80 IRS TS Operating Instructions Manual

Operating instructions

MVVS 80 IRS No: 3007L

MVVS 80 IRS SP No: 3007SP

MVVS 80 IRS TS No: 3007TS

Version 1.2

Before using the engine, please read these instructions carefully.

Congratulations on choosing the gas engine MVVS 80.
MVVS 80 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.

Technical specifications

Bore 48 mm RpM range 1000 – 7500 RpM

Stroke 44 mm

Weight of complete
engine without ignition*

2220 g Fuel Unleaded 95-octane fuel

Weight of ignition unit 190 g Lubrication Oil with petrol in mixture 1:40

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 80 engine.

4) Always use original spare parts.

5) Never tamper with the engine construction.

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

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

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

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

10) Always wear close-fitting, well-fastened clothes when starting or operating the running
engine. Never wear loosely hanging clothes (ties, scarf, etc.).

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

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

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

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

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

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

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

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

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

20) The engine power output makes it possible to fly big models. Mal-operation of such
models may cause serious damage. Start using the MVVS 80 in model planes only after
you have mastered operating smaller models.

Selecting a suitable propeller

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 engine power is best utilized when
the propeller dynamics curve and engine power curve (revolutions / power output) intersect
in the area of the engine top power output. Unfortunately, no propeller manufacturer
provides this 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.

Suggested propeller dimensions:

two-blade: 25x10-14, 26x10-14, 27x10-12
three-blade: 24x10-12, 25x10-12

These values are only approximate and may vary with the factors described in the previous
section, as well as with the type of the exhaust system used.

MVVS 80 has been designed to generate maximum power at 6000 – 6500 RpM, according
to the type of exhaust used. If you wish to utilize the maximum power output, choose a
propeller, which allow 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 using propellers with which the engine reaches more than 7000 RpM
on the ground.
When fixing the propeller to the engine tighten the central nut and each screw several times
over. Finally tighten the washer screws once again in sequence across each other.

Exhaust

Use only factory-made exhausts pipes designed for this type of engine, preferably brand­name 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.

Fuel

Strictly use unleaded 95-octane petrol mixed in the proportion 40 volume units of petrol to 1
unit of Mobil Racing 2T oil. If necessary, quality brand-name synthetic oil intended for
racing two-stroke engines can be used too.
Running the engine in, use MVVS Racing 2T oil, which come with the engine. 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.

Assembly

The engine is fastened in place with four holders built in the rear cover. The rear cover is
adjustable by 90° which ensure easy access to the carburetor’s operating elements. The
engine can be mounted directly to the firewall or an assembly kit can be used (special
accessories). Use M6 screws or screws M4 with a reduction kit (special accessories). If you
decide to fasten the engine using flexible motor mounts, always choose parts with enough
solidity and strength. Make sure to secure the screws against loosening and regularly check
that they are tightened up and in good condition.

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.

Note: Attach a hose to the airpressure inlet on the carburetor and terminate it outside the
cowl.

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.

Carburetor adjustment

Basic setting: adjusting needle (L) for low revolutions range 1 turn and 50 min

adjusting needle (H) for high revolutions range 1 turn and 10 min
(the values are derived from the position of clock-hands; the starting point is needle fully
screwed in)

The new engine comes adjusted to the basic setting. This setting should be kept during
running the engine in!

Choke lever

Adjusting needle (L)

Adjusting needle (H)

Crankcase pressure inlet

Air pressure inlet

Fuel inlet

Throttle lever

Caution! Never tight the adjusting needles by force. You can damage the touching flats for
the needles. In this way damaged parts cause the carburetor is not possible to adjust and it is
necessary to exchange new carburetor.
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 seconds

If the engine starts to run backwards do not open the throttle - stop the engine
immediately! Otherwise the engine can be damaged!

Step I

Accelerate to 2/3 of the throttle range within approx. 1 sec (faster acceleration).
Repeat three times – if the engine accelerates quickly and without a hiccup go to Step III. If
acceleration is not smooth go on to Step II.

Step II

Faulty acceleration with hiccups and a tendency to cut out is usually attributable to
a poor fuel mixture in the medium-revolutions range. Stop the engine and recheck the fuel
feed (the hose-pipe must not be pinched or broken; if fitted, check also the fuel filter
permeability). Restart the engine and test acceleration again. If problems persist adjust the
carburetor. Open the adjusting needle L by 5 min and retest acceleration. If acceleration is
smooth, open the needle by another 3-5 min - this should be done because the needle was
previously set at a boundary value; if atmospheric conditions changed during flight, the
problems might recur.

If the engine still has bad acceleration, open the needle by 10 min. If the engine’s
operation does not improve afterwards, stop it and check the basic setting. Set the adjusting
needle L at 1 turn and 50 min and the adjusting needle H at 1 turn and 10 min. Restart the
engine again and test acceleration. If the engine runs correctly go to Step III. If engine does
not accelerate properly, open the needle by another 10 min. If it does not accelerate, the
defect supposed to be elsewhere than in incorrect adjustment. In this case go to the section
on problem solving.

Step III

If the engine accelerates correctly, according to the above test, set it at idle speed
and accelerate to full speed. Repeat twice more. If the engine functions correctly, go to Step
IV. If it cuts out, open the L needle by 5-10 min more.

If the engine does not respond to acceleration fast enough keep closing the L
needle until the engine starts to cut out in response to gas. At that point reopen the L nozzle
by 5-10 min.

Step IV

If the engine reacts correctly set it at full speed. If revolutions do not drop, the
engine has been adjusted successfully. If revolutions seem to drop, open the adjusting needle
H by approx. 5-10 min.

Caution!!! The engine must be stopped while you adjust the carburetor in order to prevent
injury by the propeller.
Caution!!! Never close the choke valve completely when the engine is operating!