Ob 072 operators manual draft 1 18, Maintenance, Lehr – LEHR 2.5 HP 4-STROKE User Manual

Page 18: Greasing, Spark plug, Inspection checkpoints

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LEHR

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ALL RIGHTS RESERVED 2012-2013

16

MAINTENANCE

GREASING

NOTE: Use only water resistant grease.

Grease in these areas:

Spark plug gap:

0.020-0.024in (0.5-0.6mm)

Spark plug torque:

l8.4ft-lb (25.0Nm)

SPARK PLUG

WARNING: When removing or installing a spark plug, be careful not to damage the insulator. A damaged

insulator could allow external sparks, which could lead to explosion or fire.

The spark plug is an important engine part and is easy to inspect. The condition of the spark plug can

indicate the condition of the engine. Normally, the spark plug in a propane engine will stay very clean.

Oily or dark color ceramic could indicate a malfunction. Do not attempt to diagnose any problems yourself.

Instead, take the outboard motor to a LEHR dealer. You should periodically remove and inspect the spark

plug because the electric arcing will cause the spark plug to slowly erode and the gap will increase.

If electrode erosion becomes excessive, or if carbon and other deposits are excessive, you should replace

the spark plug with another of the correct type.

Before fitting the spark plug, measure the electrode gap with a wire thickness gauge. Adjust the gap to

specification if necessary.

When fitting the plug, always clean the gasket surface and use a new gasket. Wipe off any dirt from the

threads and screw in the spark plug to the correct torque.

NOTE: If a torque-wrench is not available when you are fitting a spark plug, a good estimate of the correct

torque is 1/4 to 1/2 a turn past finger tight. Have the spark plug adjusted to the correct torque as

soon as possible with a torque wrench.

Spark plug ID mark (i.e. NGK)

Standard spark plug: BR6H8

Spark plug Boot

INSPECTION CHECKPOINTS

Periodically check the fuel system for leaks. With the propane tank attached, and the engine cover removed,

inspect the following fuel system parts for leakage. Leaks can be identified by smell of propane or carefully

listening for a hissing sound of escaping gas. Suspected leaks can be verified by applying soapy water

solution on the area and observing bubbles forming.

Rubber access

for spark plug

wrench

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