Troubleshooting; Engine Does Not Start Or Is Hard To Start - Honda TRX70 Fourtrax 1986 Service Manual

16. TROUBLESHOOTING
ENGINE DOES NOT START OR IS
HARD TO START
POOR PERFORMANCE AT HIGH SPEEDS 16-4
ENGINE LACKS POWER
POOR PERFORMANCE AT LOW
AND IDLE SPEEOS
16-1
16-2
16-3
POOR HANDLING
ENGINE DOES NOT START OR IS HARD TO START
, . Check if fuel is getting t o NO FUEL TO • 111
carburet or CARBURETOR
,2)
'3)
GETTING TO CARBURETOR ,4)
j
2. Try spark test WEAK OR NO SPARK • (1)
'2)
GOOD SPARK
,3)
,4)
'5)
'6)
'7)
,8)
,.)
3. Test cylinder compression LOW CO MPRESSION
• (1)
'2)
COMPRESSION NORMAL
,3)
I
,4)
'5)
'6)
4. Start by following normal ENGINE STARTS BUT
• (1 )
starting procedure SOON STOPS
'2)
'3)
ENGINE DOES NOT START
I
,4)
'5)
5. Remove spark plug WET PLUG • (1)
, 2)
DRY
,3)
!
,4)
,5)
6 . Start with choke applied
16-4
ProbabM Cau ..
No fuel in fuel tank
Clogged fuel line or fuel strainer
Clogged float valve
Clogged fuel tank cap breather
hole
Faulty spark plug
Loose spark plug cap or wiring
Faulty ignition switch (After ' 86)
or engine stop switch
if
plug
sparks when black/white wire is
disconnected
Faulty exciter coil
Faulty pulse generator
Faulty ignition coil
Faulty COl
Pulse generator air gap
Loose terminals , connectors.
faulty wiring
Valve clearance too small
Valve stuck open
Worn cylinder and piston rings
Damaged cylinder head gasket
Seized valve
Improper v elve timing
Choke stuck c losed
Improperly adjusted pilot screw
Air leaking past carburetor insula·
to,
Improper ignition timing (COl unit
or pulse generator faulty)
Fuel/air mixture too lean
Carburetor flooded
Choke stuck open
Fuel/air mixture too rich
Air cleaner dirty
Improperly adjusted pilot screw
16-1