Guardian Technologies 4451 & 4986 Manual De Usuario

PROCEDURE:
1. Remove the fuel line from the fuel filter on the inlet side of the

carburetor. Use a suitable catch can to catch fuel.

2. Crank the engine over, fuel should flow from the fuel line. If fuel

does not flow, verify that fuel is available to the pump. If fuel is
available to the pump inspect the fuel filter, pulse line, and or
replace the fuel pump.

RESULTS:
Refer to flow chart.

PROCEDURE:
Before making a carburetion check, be sure the fuel sup-

ply tank has an ample supply of fresh, clean gasoline.
Check that all shutoff valves are open and fuel flows 

freely through the fuel line.
Make sure the choke operates properly.
If the engine will not start, remove and inspect the spark 

plug. If the spark plug is wet, look for the following:
•  Overchoking. 
•  Excessively rich fuel mixture. 
•  Water in fuel. 
•  Intake valve stuck open.
•  Needle/float stuck open.
If the spark plug is dry look for the following:
•  Leaking carburetor mounting gaskets. 
•  Intake valve stuck closed. 
•  Inoperative fuel pump. 
•  Plugged fuel filter(s).
•  Varnished carburetor
If the engine starts hard or will not start, look for the 

following:
•  Physical  damage  to  the  AC  generator.  Check  the 

Rotor for contact with the Stator.

•  Starting under load. Make sure all loads are discon-

nected or turned off before attempting to crank and 

start the engine.

•  Check that the choke is working properly.
1. Remove  fuel  line  at  carburetor  and  ensure  that  there  is  an

adequate amount of fuel entering the carburetor.

2. Remove the float bowl and check to see if there is any foreign

matter in bottom of carburetor bowl.

3. The  float  is  plastic  and  can  be  removed  for  access  to  the

needle so it can be cleaned.

4. With  all  of  this  removed  carburetor  cleaner  can  be  used  to

clean the rest of the carburetor before reassembly.

5. After cleaning carburetor with an approved carburetor cleaner,

blow dry with compressed air and reassemble.

Shelf  life  on  gasoline  is  30  days.  Proper  procedures 

need to be taken for carburetors so that the fuel doesn’t 

varnish  over  time.  A  fuel  stabilizer  must  be  used  at  all 

times in order to ensure that the fuel is fresh at all times.

RESULTS:
If  carburetor  is  varnished,  clean  or  replace.  Refer  to 

Flow Chart.

ADJUSTING VALVE CLEARANCE:
The valve lash must be adjusted correctly in order to pro-

vide the proper air/fuel mixture to the combustion chamber.
Adjust  valve  clearance  with  the  engine  at  room  tem-

perature. The  piston  should  be  at  top  dead  center 

(TDC) of its compression stroke (both valves closed). 
An alternative method is to turn the engine over and 

position the intake valve fully open (intake valve spring 

compressed) and adjust the exhaust valve clearance. 

Turn  the  engine  over  and  position  the  exhaust  valve 

fully  open  (exhaust  valve  spring  compressed)  and 

adjust the intake valve clearance.
Correct valve clearance is given below.

FEELER GAUGE

ALLEN WRENCH

1. Loosen the rocker arm jam nut. Use a 10mm allen wrench to

turn the pivot ball stud while checking the clearance between
the rocker arm and valve stem with a feeler gauge (see Figure
6-51).

2. When  clearance  is  correct,  hold  the  pivot  ball  stud  with  the

allen wrench and tighten the rocker arm jam nut to the specified
torque with a crow's foot. After tightening the jam nut, recheck
valve clearance to make sure it did not change.

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