Crank Bearings.

Adjusted too

Overheating be-

Adjust freely, clean Main Bearings.

tight. Defective

cause of friction.

out oil holes and

oiling. Bra.s.ses

enlarge oil grooves.

burned.

Oil Sump.

Insufficient oil.

Overheating.

Replenish supply.

Poor lubricant.

Use best oil. Wash

Dirty oil.

out with kerosene;

put in clean oil.

Water s.p.a.ce. Water

Clogged with sedi-

Overheating.

Dissolve foreign Pipes.

ment or scale.

matter and remove.

Piston Head.

Cracked (rare).

Loss of compres-

Weld by autogenous

Carbon deposits.

sion. Preignition.

process. Sc.r.a.pe off

carbon acc.u.mula-

tions.

NOISY OPERATION OF POWER PLANT

------------------+------------------+------------------+-------------------- PART AFFECTED

NATURE OF TROUBLE

CHARACTER OF

REMEDY

NOISE

------------------+------------------+------------------+-------------------- Compression Re-

Leakage.

Hissing.

Previously given.

lease c.o.c.k.

Spark Plug.

Leakage.

Hissing.

Previously given.

Valve Chamber Cap.

Leakage.

Hiss or whistle.

Previously given.

Combustion

Carbon deposits.

Knocking.

Previously given.

Chamber.

Inlet Valve Seat.

Defects previously

Popping in carbu-

Previously given.

given.

retor.

Valve Head.

Loose on stem.

Clicking.

Previously given.

Valve Stem. Valve

Wear or looseness.

Rattle or click-

Previously given.

Stem Guide.

ing.

Inlet Valve.

Closes too late.

Blowback in carbu-

Previously given.

Opens too early.

retor.

Valve Spring.

Weak or broken.

Blowback in carbu-

Previously given.

retor.

Cylinder Casting.

Retaining bolts

Sharp metallic

Tighten bolts. Round

loose. Piston

knock.

edges of piston

strikes at upper

top.

end.

Cylinder Wall.

Scored.

Hissing.

Previously given.

Valve Stem

Too much.

Clicking. Blowback

Previously given.

Clearance.

Too little (inlet

in carburetor.

valve).

Valve Operating

Looseness.

Rattle or click-

Previously given.

Plunger. Plunger

ing.

Guide.

Timing Gears.

Loose on fasten-

Metallic knock.

Previously given.

ings. Worn teeth.

Rattle. Grinding.

Cylinder or

No oil, or poor

Grinding.

Repair oil system.

Piston.

lubricant.

Cam.

Loose on shaft.

Metallic knock.

Previously given.

Worn contour.

Cam-shaft Bearing.

Looseness or wear.

Slight knock.

Previously given.

Cam Fastening.

Looseness.

Clicking.

Previously given.

Piston.

Binding in cylin-

Grinding or dull

Previously given.

der. Worn oval,

squeak. Dull

causes side slap

hammering.

in cylinder.

Piston Head.

Carbon deposits.

Knocking.

Previously given.

Piston Rings.

Defective oiling.

Squeaking. Hiss-

Previously given.

Leakage. Binding

ing. Grinding.

in cylinder.

Wrist-pin.

Loose in piston.

Dull metallic

Replace with new

Worn.

knock.

member.

Connecting Rod.

Wear in upper

Distinct knock.

Adjust or replace.

bushing. Wear at

Sc.r.a.pe and fit. Use

crank-pin. Side

longer wrist-pin

play in piston.

bushing.

Crank Bearings.

Looseness. Exces-

Metallic knock.

Refit bearings.

sive end play.

Intermittent

Longer bushings

Binding, fitted

knock. Squeaking.

needed. Insert shims

too tight.

to allow more play.

Main Bearings.

Looseness. Defec-

Metallic knock.

Fit bra.s.ses closer

tive lubrication.

Squeaking.

to shaft. Clean out

oil holes and

grooves.

Connecting Rod

Loose.

Sharp knock.

Tighten.

Bolts. Main

Bearing Bolts.

Crank-shaft.

Defective oiling.

Squeaking.

Previously given.

Engine Base.

Loose on frame.

Sharp pounding.

Tighten bolts.

Lower Half Crank-

Bolts loose.

Knocking.

Tighten bolts.

case.

Fly-wheel.

Loose on crank-

Very sharp knock.

Tighten retention

shaft.

bolts or fit new

keys.

Oil Sump.

Oil level too low.

Grinding and

Replenish with best

Poor lubricant.

squeak in all

cylinder oil.

bearings.

Valve Plunger Re-

Looseness.

Clicking.

Tighten nuts.

tention Stirrups.

Fan.

Blade loose. Blade

Clicking or

Tighten. Bend back.

strikes cooler.

rattle.

Exhaust Pipe

Leakage.

Sharp hissing.

Tighten or use new Joints.

gasket.

Crank-case

Leakage.

Blowing sound.

Use new packing.

Packing.

Tighten bolts.

Water Pipe.

Leaks. Loss of

Pounding because

Previously given.

water. Clogged

engine heats.

with sediment.

Water Jacket.

Clogged with sedi-

Knocking because

Dissolve scale and

ment. Walls

engine heats.

flush out water

covered with

s.p.a.ce with water

scale.

under pressure.

"SKIPPING" OR IRREGULAR OPERATION

------------------+------------------+------------------+-------------------- PART AFFECTED

NATURE OF TROUBLE

SYMPTOMS AND

REMEDY

EFFECTS

------------------+------------------+------------------+-------------------- Compression Relief

Leak in threads or

Dilutes mixture

Screw down tighter.

c.o.c.k.

spigot.

with air, causes

Grind spigot to seat

blowback.

with emery.

Spark-Plug.

Leak in threads.

Dilutes mixture.

Screw down tighter.

Defective gasket.

Allows short

Replace with new.

Cracked insulator.

circuit. No spark.

Set points 1/64"

Points too near.

apart for magneto,

Points covered

1/32" for battery

with carbon. Too

spark.

much air gap.

Valve Chamber Cap.

Leak in threads.

Dilutes mixture by

Previously given.

Defective gasket.

allowing air to

enter cylinder on

suction stroke.

Combustion

Carbon deposits.

Preignition.

Sc.r.a.pe out.

Chamber.

Valve Head.

Warped or pitted.

Dilutes charge

Previously given.

Loose on stem.

with poor air or

gas.

Valve Stem.

Binding in guide.

Irregular valve

Previously given.

Sticking.

action.

Valve Seat.

Scored or warped.

Gas leak, poor

Previously given.

Cracked. Covered

mixture. Poor com-

with scale. Dirt

pression. Valve

under valve.

will not close.

Induction Pipe.

Leak at joints.

Mixture diluted

Stop all leaks.

Crack or blowhole.

with excess air.

Inlet Valve.

Closes too late.

Blowback in carbu-

Time properly.

Opens too early.

retor.

Exhaust Valve.

Opens too late.

Retention of burnt

Time properly.

Closes too early.

gas dilutes

charge.

Valve Stem Guide.

Bent or carbon-

Causes valve to

Previously given.

ized.

stick.

Inlet Valve Stem

Worn, stem loose.

Air drawn in on

Bush guide or use Guide.

suction thins gas.

new member.

Valve Spring.

Weakened or

Irregular action.

Use new spring.

broken.

Valve Stem

Too little. Too

Valve will not

Adjust gap .009"

Clearance.

much.

shut. Valve opens

inlet, .010"

late, closes

exhaust.

early.

Valve Spring

Broken.

Releases spring.

Replace.

Collar Key.

Cam.

Worn cam contour.

Valve lift re-

Previously given.

Loose on shaft.

duced. Does not

Out of time.

lift valve. Valves

operate at wrong

time.

Cam-shaft Bearing.

Looseness or wear.

Valve timing

Replace.

altered. Valve

lift decreased.

Cam-shaft.

Twisted.

Valves out of

Previously given.

time.

Cam Fastening.

Worn or broken.

Valve action

Replace with new.

irregular.

Valve Operating

Loose in guide.

Alters valve

Replace with new.

Plunger.

timing.

Valve Plunger

Wear in bore.

Alters valve

Replace or bush.

Guide.

Loose on engine

timing.

Fasten securely.

base.

Timing Gears.

Not properly

Valves out of

Retime properly.

meshed. Loose on

time. Valves do

Fasten to shaft.

shaft.

not operate.

Piston.

Walls scored.

Leakage of gas.

Smooth up if

possible.

Piston Head.

Carbon deposits.

Cause premature

Previously given.

Crack or blowhole

ignition.

(rare).

Piston Rings.

No spring. Loose

Leakage weakens

Previously given.

in grooves. Worn

suction.

or broken.

Cylinder Wall.

Scored by wrist-

Gas leaks by. Poor

Previously given.

pin. Scored by

suction.

lack of oil.

------------------+------------------+------------------+--------------------

IGNITION SYSTEM TROUBLES ONLY

_Motor Will Not Start or Starts Hard_

Loose Battery Terminal.

Magneto Ground Wire Shorted.

Magneto Defective (No Spark at Plugs).