Your MERCO engine is the product of considerable design and development work, all aimed at making it easy to operate. The MERCO is extremely powerful and due to exclusive design features, it is also easy to start, flexible in fuel adjustment, and very economical in fuel consumption. It is outstanding in its ability to give a smooth engine run under aerobatic flying conditions in both control-line and radio models.

The MERCO design is the result of development over a long period of time under actual flying conditions, motors having been flown in national and international contests.

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Run your MERCO engine in for at least 30 minutes on half throttle before attempting to fly. If during the next 30 minutes of lying time the engine slows down through overheating, slow throttle should be used for about 30 to 60 seconds. This will cool the engine down while in flight. It is therefore advisable to fly fairly high for the first 30 minutes.

A straight fuel with 25% castor oil and 75% methanol is recommended. Do not use a fuel mix with only synthetic oil. Castor is much better for engine life. For further details on recommended fuels see later on in this leaflet

Connect up a leak-free tank, open the needle valve 1-3/4 complete turns. Choke the fuel round from the tank to jet, and give two extra chokes to get a charge of fuel into the crankcase. Then carefully inject a small quantity of fuel through the exhaust port onto the top of the piston. Flick the prop a couple of times in order to get everything freed up, and connect your battery leads, one to the top of the plug and one to the body of the engine. Several sharp flicks should then start the engine. Failure to start can only mean one or more of the following faults:

(1) No glow. Check that your battery is in a good state of charge. Also, check your battery leads for breakages and check your plug. You should be able to see a bright orange glow by looking into the exhaust port with your battery leads connected and with the piston at the bottom of its stroke.

(2) Lack of fuel. A short sharp burst from the engine means that it is set too lean. Open up the needle valve another 1/2 turn and try again.

(3) Too much fuel. A dull red glow coupled with a faint sizzling sound from inside the engine means that the engine is too rich. Disconnect the plug lead, close the needle valve right down and flick the prop several times to remove the excess fuel. When this is cleared, open up the needle valve half a turn less than the original setting and start again.

Before attempting to adjust the throttle for idle, set controls as follows:

(1) Holding throttle lever in open position, screw in idle needle until resistance is felt, then unscrew idle needle 4 complete turns.

(2) Now holding throttle lever in closed position, adjust throttle stop screw until gap A is approximately 3/64".

(3) Open main needle 2-1/2 complete turns and start the engine, let the engine attain running temperature and tune for peak RPM with main needle as usual.

(4) Close throttle and allow engine to idle for a few seconds, open throttle and if engine picks up slowly with excess smoke screw in idle needle. If engine cuts, unscrew idle needle.

(5) Now adjust throttle stop screw for slow idle, finally re-adjust idle needle if necessary. The settings may have to be altered after break in period.

(6) If settings are lost it is advisable to go back to step no. 1.

All the above instructions apply to marine units with the addition of the following:

Do not run your engine flat out without load.
Do not run your engine without water flowing through the water jacket.

Failure to observe these two rules will result in expensive damage.

Use prop recommended for your boat.

All engines should be returned direct to the makers for repair. When returning your engine, please state briefly the nature of the repair required. An estimate of the cost of repair will be sent to you before any work is undertaken.

Minor repairs will be carried out for a nominal service charge plus the cost of all necessary spare parts and postage and packing.

Once all throttle settings are established, the following procedure for starting is suggested. Open throttle, choke with finger and flick prop 3 or 4 times, shut throttle to within 1/16" of fully closed, connect glow lead, flick prop until engine starts. As engine warms up, open throttle ready for takeoff.

If you find that your engine is running "rich" on takeoff and then tending to cut out in the air, fit new plugs. The platinum element in the plug oxidises with use and then loses efficiency when it is not connected to the battery.

Before attempting to take your engine apart, please read Part 1 of your guarantee.

Do not dismantle your engine unless absolutely necessary. However, if you feel that it is essential:

1. On no account disturb the crankshaft and bearings in the crankcase;
2. Do not spin crankshaft unless it is (a) clean and (b) lubricated;
3. Wash all parts in clean methanol;
4. Lightly oil all moving parts with 3 in 1;
5. When reassembling, use the cross system to tigthen the head-screws. It is imperative that when tightening these screws each screw should exert the same pressure on the head at any one time - if one screw causes more stress to the head than others, your engined could be damaged.

The operating and care procedures that apply to MERCO engines with piston rings also apply to MERCO ABC engines but the running in methods differ. The chrome-plated brass liner in an ABC engine is minutely tapered at the top end but the hardened steel liner in a "ringed" engine is perfectly parallel. An ABC engine does not have a piston ring; the cast aluminum piston fits perfectly inside the liner to create the compression seal and when new, the taper causes the piston to feel tight as it nears top-dead-centre. A "ringed" engine will not exhibit such tightness. A piston ring is fitted into a piston ring groove and the piston fits loosely into the steel liner. The sprung piston ring expands against the liner to create the compression seal. Both types of engine prefer castor fuel mixture.

It is much easier to run in an engine on a test-bench before installation into a model. Running in a "ringed" engine is described in the instruction manual. An ABC engine requires longer to run in but the extra time is well worth while; a carefully run in engine will last longer and develop much more power. Start the engine in the usual manner by hand or starter motor and run on a rich mixture at about half speed for ten minutes then allow to cool. If the engine slows down due to overheating at any time, stop, allow to cool, and start again. Repeat the minute run-and-cool procedure at least four more times progressively leaning out the mixture and speeding up the engine on each occasion until peak RPM can be achieved and maintained.