Briggs & Stratton 700 DOV Series, Repair Manual

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1
2
Figure 2 - 2
If spark does not occur, look for:
• Improperly operating interlock system
• Shorted equipment or engine stop switch
wire
• Incorrect armature air gap
• Armature failure
2) Check Carburetion
Before making a carburetion check, be sure the
fuel tank has an ample supply of fresh, clean
gasoline.
Be sure the shutoff valve, if equipped, is open
and fuel flows freely through the fuel line. If fuel
fails to flow or is slow, check for plugged fuel cap
vent, fuel line restriction or plugged fuel filter.
Be sure throttle and choke controls are properly
adjusted.
If engine cranks but will not start, remove and
inspect the spark plug.
If plug is wet, look for:
• Over choking
• Excessively rich fuel mixture
• Water in fuel
• Float needle valve stuck open
• Plugged air cleaner
• Fouled spark plug
If plug is dry, look for:
• Leaking carburetor or intake manifold
gaskets
• Gummy or dirty carburetor, fuel filter, fuel
lines or fuel tank
• Float needle valve stuck closed
• Inoperative fuel pump (if equipped)
• Inoperative fuel shut off solenoid (if
equipped)
A simple check to determine if the fuel is getting
to the combustion chamber through the
carburetor is to remove the spark plug and pour
a small quantity of gasoline through the spark
plug hole. Replace the plug. If the engine fires a
few times and then stops, look for the same
conditions as for a dry plug.
3) Check Compression
Use Leakdown Tester #19545 to check the
sealing capabilities of the compression
components.
Follow the instructions provided with the tester to
perform the leakdown test.
NOTE: Any air leaks at the connections or
fittings of the tester will affect the accuracy of the
test.
Listen for air leaking from the cylinder head
gasket, carburetor, exhaust system, and the
crankcase breather tube.
• Air flowing between the cylinder and
cylinder head indicates that the cylinder
head gasket is leaking.
• Air flowing from the carburetor indicates
air is leaking past the intake valve and
seat.
• Air flowing from the exhaust system
indicates air is leaking past the exhaust
valve and seat.
• Air flowing from the crankcase breather
tube or high oil fill dipstick tube indicates
air is leaking past the piston rings.
Possible Causes for Poor Compression:
• Loose cylinder head bolts
• Blown head gasket
• Burned valves, valve seats and/or loose
valve seats
• Insufficient tappet clearance
• Warped cylinder head
• Warped valve stems
• Worn bore and/or rings
• Broken connecting rod