Engine Installation - O.S. engine max-18tz series Owner's Instruction Manual

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GLOWPLUG

Since the compatibility of the glowplug and fuel

may have a marked effect on performance and

reliability, it may be worthwhile to choose the

R/C type plug found most suitable after

tests. Recommended O.S. plugs are P3 and P6.

Carefully install plug finger-tight, before final

tightening with the correct size plug wrench.

The role of the glowplug

With a glowplug engine, ignition is initiated by the

application of a 1.5-volt power source. When the

battery is disconnected, the heat retained within the

combustion chamber remains sufficient to keep the

plug filament glowing, thereby continuing to keep the

engine running. Ignition timing is 'automatic' : under

reduced load, allowing higher rpm, the plug becomes

hotter and, appropriately, fires the fuel/air charge

earlier; conversely, at reduced rpm, the plug become

cooler and ignition is retarded.

INSTALLATION OF THE CARBURETOR

As delivered, the engine has its carburetor

lightly fit into the intake boss. Secure it as

follows.

Loosen the retainer screw, rotate the

carburetor to its correct position and make

sure that it is pressed well down into the

intake boss, compressing the rubber gasket,

before retightening screw.

Rotate the retainer screw gently until it

stops, then tighten a further 60-90˚.

Do not overtighten the screw as this will

damage the carburetor body.

Rotate the retainer nut

gently until it stops.

Tighten a further 60-90˚

Glowplug life

Particularly in the case of very high performance

engines, glowplugs must be regarded as expendable

items. However, plug life can be extended and engine

performance maintained by careful use, i.e.:

Install a plug suitable for the engine.

Use fuel containing a moderate percentage of

nitromethane unless more is essential for racing

events.

Do not run the engine too lean and do not leave the

battery connected while adjusting the needle.

When to replace the glowplug

Apart from when actually burned out, a plug may

need to be replaced because it no longer delivers its

best performance, such as when:

Filament surface has roughened and turned white.

Filament coil has become distorted.

Foreign matter has adhered to filament or plug

body has corroded.

Engine tends to cut out when idling.

Starting qualities deteriorate.