Will not start. No spark at spark plug. Gas OK.

You changed plugs but did you check the spark, is it still sparking ok when the engine dies?

If the spark is ok the problem is likely to be fuel and a thorough fuel system clean is advisable.

Only two things can cause this (1) not getting gas and or (2) not getting spark.
Have someone crank while you hold spark plug wire just of off spark plug, if you see spark from wire too motor block then put a little gas into carb and see if it fires if it fires then look for a gas line or gas tank problem.

Make sure the battery is fully charged. Consider getting a jump from another vehicle and if that doesn't work buy a can of ether starting fluid from the local walmart or auto store. Make sure not to keep turning the motor over if the vehicle doesn't start - you will flood the motor with gas and can damage the pistons - excessive gas will wash off the oil and the starter will get very hot. If you have done that already consider removing the spark plugs and adding a few drop of engine oil to each cylinder and smell for gas - let it air out. When older cars sit unused problems can bubble up.

if flooding with gas replace needle and seat in carb take plug out pull starter cord to clear clinder make sure no gas in oil pull dipstick find out ok put the plug back in then squirt some starting fliud in carb start motor up

Providing that your timing belt is ok and your engine tune up is such that the engine was running smoothly, you need three basic things for the engine to turn on. 1) Air and 2) fuel 3)Spark. To see if you are getting a spark, you can disconnect a spark plug wire from the spark plug and lay it next to the engine. have someone crank the engine over and listen for a spark sound. You will probably not be able to see the spark during the day. you can see the spark if it's dark outside. if you have a spark then connect the spark plug wire back to the spark plug. disconnect the hose from the throttle body. This hose comes from the air filter housing to the throttle body. Have someone hold the gas pedal down and spray some engine starter fluid that you can buy at the auto parts. Release the gas pedal, then hold the gas pedal down slighly and crank the engine. If the engine turns on and then turns off, check to see if you are not out of gas. if gas level is ok, your fuel filter may need to be replaced.

check for spark at the coil first for a spark. if ok check for spark on the ignition leads at the spark plug.if ok take off the leads one at a time remove the spark plug .smell it for fuel .if smell found .chnge your spark plugs.

Basics to check:
1) Spark plug - brown or dark brown - OK
a) is it carbon or fuel fouled
b) is there spark

2) Muffler remove for inspection
a) exhaust screen clean or plugged
b) inspect cylinder wall/piston as the flywheel is slowly rotated
3) Check cylinder compression


Fuel starvation - 'lean fuel' condition
Basic things to check:
1) spark plug
2) spark arrestor in muffler
3) fuel lines and tank filter
4) turn adjustment needles out (counterclockwise) 1/4 to 1/2 turn
Chain Saws:
5) check impulse tube and intake boot for cracks or leaks
*if all of the above are OK and/or do not improve performance then:
Remove Carburetor
6) replace gaskets/diaphragms
a) use a spray carb cleaner to clean jets, holes, and body of carb
b) fuel pump diaphragm goes against the carb body,
then the gasket towards the outside
c) metering gasket goes against the carb body,
and the diaphragm goes towards the outside

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If the starter/Battery are ok.Check for spark by pulling off a sparkplug wire,have someone try to start hold wire near sparkplug tip you'll hear the spark jump to the plug tick..tick..tick..sound.Be carefull to hold wire just far enough to hear spark,also this is the secondary circuit from the coil it's high voltage wear a glove.If you smell gas youre geting gas if no spark it is 1 of the following.Bad Coil, or ignition modulator, crack in distributer, cracked wires that cause spark to not reach plugs.Good Luck.

Check the gas and gas tank, you might have water in the gas.

check that plug is getting spark (remove plug, w/ cap attached hold tip of plug on cooling fin. pull starter rope, should see spark). if not receiving gas check filter in tank, if ok procede to carb possibly add a bit of starter fluid.