Before making a Carburetion check, be sure the fuel
tank has an ample supply of fresh, clean gasoline.
On gravity feed (Flo-Jet) models, see that the
shut-off valve is open and fuel flows freely through the
fuel line. On all models, inspect and adjust the needle
valves. Check to see that the choke closes completely. If
engine will not start, remove and inspect the spark plug.
If plug is wet, look for -
Excessively rich fuel mixture
Water in fuel
Inlet valve stuck open (Flo-Jet carburetor)
If plug is dry, look for -
Leaking carburetor mounting gaskets
Gummy or dirty screen or check valve (Pulsa-Jet
and Vacu-Jet carburetors)
Inlet valve stuck shut (Flo-Jet carburetors)
Inoperative pump (PulsaJet carburetors)
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 quits, look for the
same condition as for a dry plug.
Equipment - Effecting Engine Operation
Frequently, what appears to be a problem with engine
operations, such as hard starting, vibration, etc., may be
the fault of the equipment powered rather than the
engine itself. Since many varied types of equipment are
powered by Briggs and Stratton engines, it is not
possible to list all of the various conditions that may exist.
Listed are the most common effects of equipment
problems, and what to look for as the most common
Hard Starting, Kickback, or Will Not Start
Loose blade must be tight to shaft or adapter.
Loose belt a loose belt like a loose blade can
cause a back-lash effect, which will counteract
engine cranking effort.
Starting under load See if the unit is disengaged
when engine is started; or if engaged, does not
have a heavy starting load.
Check remote Choke-A-Matic control assembly
for proper adjustment.
Check interlock system for shorted wires, loose
or corroded connections, or defective modules
Cutter blade bent or out of balance Remove and
Crankshaft bent - Replace
Worn blade coupling - Replace if coupling allows
blade to shift, causing unbalance.
Mounting bolts loose - Tighten
Mounting deck or plate cracked Repair or
Bind or drag in unit If possible, disengage engine
and operate unit manually to feel for any
Grass cuttings build-up under deck.
No lubrication in transmission or gear box.
Excessive drive belt tension may cause seizure.
Cutter blade coupling or pulley an oversize or
worn coupling can result in knocking, usually
under acceleration. Check for fit, or tightness.
No lubricant in transmission or gear box.