Operating instructions
MVVS 116 IRS No: 3010
Version 1.3
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Before using the engine, please read these instructions carefully.
Congratulations on choosing the gas engine MVVS 116cc.
MVVS 116cc 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
Stroke
Weight of complete engine
without ignition*
Weight of ignition unit
RpM range
* Some manufacturers state the weight of incomplete engines. 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.
42 mm
42 mm
3100 g
270 g
1000 – 7500 RpM
Maximum power output **
Silencer INT 58.01+MVVS adaptor
Maximum torque **
Silencer INT 58.01+MVVS adaptor
Fuel
Lubrication
14 HP/6400 RpM
11 PS/6000 RpM
15N/m / 6100 RpM
12.7N/m 5600 RpM
Unleaded 95-octane fuel
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 driven
by MVVS 116cc engine.
4) Use always 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 (tie, 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 116cc 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.
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Suggested propeller dimensions:
two-blade propellers:
28x10-14, 30x10-12, 32x10
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.
Fuel
Always 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.
For running the engine in, please use MVVS Racing 2T oil that comes 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.
Assembly
The engine is fastened to place by four holders built in the rear cover. The engine can be mounted directly to the firewall or an assembly
kit can be used (special accessories). Use screws M6. 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 hot air outlet – which
must be higher than the intake one. Gas engines heat up to higher degree than methanol one!
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 air-pressure inlet on the carburetor and terminate it outside the cowl.
For fuel supply use the hose delivered only, this diameter ensure the sufficient fuel supply in each turn and minimize the flow resistance.
Use of the smaller hose can cause engine turn off by the turning with high G-forces.
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.
Exhaust
Use only factory-made exhausts pipes designed for this type of engine. Preferably MVVS exhaust system, which also guarantees the
announced power output.
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.
System CON JET (Control Jet) is the highest HI-TECH level for your acceleration!
Your engine is equipped by unique system firstly used by diagraph carburetors. This system allows mixture to be controlled in process
of throttle valve opening. Thanks to this system the mixture is leaned while low RpM and idle. Conversely the mixture becomes richer
by the throttle opening. This system brings better acceleration and stable run while low RpM.
This system was developed by MVVS for 116cc engine by use of advanced measuring equipment; therefore do not try to change the
mixture control leverage. The engine could be damaged.
Carburetor adjustment:
Carburetor is adjusted before you buy it. It is not usually needed to change this setting (always apply if used recommended exhaust
system and propeller). Con-Jet system brings you one more bonus as well. In most common flights you will need to set up the main
nozzle only (except races).
Caution! All settings make only if engine does not run. Injury may be caused by propeller Never interfere into nozzle control leverage.
Basic setting: adjusting needle (L) for low revolutions range: 45 min (by the throttle closed, by throttle opened it is: 65 min.)
adjusting needle (H) for high revolutions range 50 min – 1 turn
(the values are derived from the position of clock-hands, starting position: fully closed needle)
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The new engine comes adjusted to the basic setting. This setting should be kept during the
engine running in!
Caution! Newer turn the needles tight, the seat can be so damaged and the carburetor is no
more possible to set, must be replaced for the new ones. Especially by the turning the L
needle: the needle is fitted in the elastic sleeve into lever, which allows turning the needle.
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 could 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 mediumrevolutions 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 continues to malaccelerate open the needle by 10 min if the engine’s operation does not improve, stop it and
check the basic setting. Set the adjusting needle L at 50 min and the adjusting needle H at 1 turn . Restart the engine and test
acceleration. If the engine runs correctly go to Step III. If it continues to malaccelerate, open the needle by another 10 min. If it
keeps malaccelerate, the defect is likely to lie elsewhere than in incorrect adjustment. In such a 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! The choke valve is set to allow minimum air flow
only when fully closed, which could cause damage to the intake reed valve.
Starting and running a new engine in:
Before you first start the engine, make sure that the plug is screwed in and tightened up and that the plug socket is fitted in place and
fastened down properly.
Fix the ignition sensor in proper position above the magnet per screws enclosed.
Unless the spark plug is not inserted in plug socket, never turn the engine with ignition turned on.
This could lead to ignition damage!
1) Make sure that the ignition is switched off, the choke valve is closed and the throttle valve is about half opened. Then give the engine
3-4 turns, provided that carburetor is not overflowing. If it is overflowing, give the engine 1-2 turns only.
2) Switch the ignition on, open the choke valve, set the throttle at slightly higher idle speed and give the engine a few quickly turns. If
even after the fourth turn, with the choke valve closed, you do not hear a suggestion of the engine starting, give the engine 2 turns
following the instructions in paragraph 1 above. Then proceed according to instructions given in paragraph 2.
3) If the engine does not start even after another set of turns open the throttle to maximum and give the engine approx. 4 turns. Switch
the ignition off and on again and restart the engine with throttle turned slightly down and the choke valve set open.
4) If the engine still would not start, unscrew the plug and check its contacts. Clean any possible petrol moisture ( i.e. an indication of
engine overflow ) and screw it in again. Further starting should only be done with the throttle turned down. If the plug is dry then
probably not enough fuel has been drawn into the carburetor. If that is the case, check the fuel feed and then return to the instructions
given in paragraph 1.
If the engine starts to run backwards do not open the throttle - stop the engine immediately! Otherwise the engine could be
damaged!
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While the engine has been started, leave it run for approx. 5 min at a higher idle speed. Then run it in for approx. 20 min, while
changing revolutions from idle to 1/2-3/4 of the range and shortly holding each position - gradually prolong the holding periods. After
10 minutes running, start opening the throttle at maximum for short periods of time. Stop the engine and let it cool down. Then restart it
and check the adjustment. If everything is all right, you can first take off. During first few flights do not overload the engine and do not
let it run at high revolutions for long periods of time (very important at hot weather). Use up all fuel that was produced as a mixture with
the oil that is included in the package. From now on, fuel and oil should be mixed in the proportion 40:1.
The MVVS 116 is designed for the power maximum by 5800 – 6300 RpM (according the exhaust pipe used). If this maximum
performance is needed, choose the suitable propeller so, the engine reach these speed on the ground (in fact slightly lower; depends on
the unloading the propeller in air in accordance to reached speed while flying)
We do not recommend use of propellers, which allows turning the engine on the ground more as 7000 RpM.
Problem guide
The engine would not start:
– check the battery voltage; use the good brand battery only
– check and or replace the spark plug if needed (check the spark by inserting the plug into the plug socket and turning the
engine)
– check the fuel supply
– turn the engine to check its mechanical condition
– check whether the carburetor nozzles are adjusted correctly
– take the carburetor off and visually examine the condition of the carbon-fiber reed valve
– unscrew the carburetor cover on the side of the pressure inlet, check the fuel screen possibly give the carburetor a blow with a
current of air; when reassembling, make sure you arrange the membrane and gasket in a correct order
– recheck the pressure hose attached to the carburetor
Replacing the reed valve:
– unscrew and remove the carburetor (mind the gasket)
– unscrew four M4 screws on the flange, remove the flange and take off the reed valve (mind the gasket)
– unscrew four M2 screws and remove the old valves, replace them with new ones, screw the screws back in and tighten them
gently
– when reassembling, make sure you fix the gasket correctly
Mechanical faults of the engine:
Turning the engine is not possible. Probable error: the piston in the cylinder got seized:
– slacken and unscrew the M5 nuts under the cylinder (to slacken the screws use a special wrench only, which you can order as
an accessory)
– carefully remove the cylinder
– you will probably be able to find out the probable error of the engine’s mechanical problem by visually examining the piston
and crankcase.
– mechanical repairs must always be commit to a professional service department
Service information
After each 20 hours of running or 1 year change the spark plug.
After each 50 hours of operation time preventively check up the con-rod and the reed valve.
After 300 hours of operation time commit the engine to the professional warranty service department.
Warranty
The MVVS gas engines come with a two-year guarantee against defects in workmanship and materials. Only original buyers of the
engines are eligible warranty claimants. The warranty cannot be transferred with a change in ownership.
This guarantee does not cover:
- any normal wear that might occur
- damage arising from accidents
- damage arising from the use of an unbalanced or damaged propeller
- damage arising from the use of a too small or a too big propeller
- damage arising from the use of low-quality fuel
- damage arising from the use of other than original spare parts and accessories
- damage arising from sucking a foreign object into the engine
- damage arising from any improper use
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For further questions, please contact:
MVVS, spol. s r.o., tr. Kpt. Jarose 35, 602 00 Brno, Czech Republic
Ph.: +420 545 211 683, fax: +420 545 211 418
E – Mail: mvvs@mvvs.cz
Nr.: Description: Nr.: Description:
0101 Crankcase 1102 Drive washer key
0102 Crankcase screws-set 1103 Propeller nut
0202 Front bearing 1104 Propeller washer
0204 Packing 1105 Propeller screw
0203 Rear bearing 1107 Propeller screws - set
0304 Rear cover bearing 0306 Carburetor flange
0302 Rear cover screws-set 0307 Carb. flange gasket
0304 Pressure nipple 0308 Carb. flange screws - set
0401 Cylinder 1301 Reed valve case
0402 Cylinder screws - set 1302 Reed valve
0403 Cylinder nut 1303 Reed valve screws
0404 Cylinder gasket 1304 Reed valve gasket-upper
0405 Exhaust screws - set 1305 Reed valve gasket-bottom
0406 Exhaust nut 1306 Reed valve strap
0407 Exhaust flange gasket 1307 Carburetor screws
0701 Piston 3314B Electronic ignition unit
0702 Piston ring 3309 Spark plug
0801 Piston pin 1405 Ignition sensor fixing screws
0802 Piston pin retainer 3228 Carburetor
1001 Crankshaft
1101 Drive washer
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