80 720 wont start

[Justice4kurt182]

started christmas day of '12, (merry christmas right?) started my truck and it ran rough
(sounded more like a harley then usual) shut it off and three days later wouldnt start at all. replaced fuel filter, pulled and cleaned plugs, replaced cap rotor and eventually the dizzy. still no go. truck will crank and spark sometimes back fire. any thoughts?

[datzenmike]

Take air filter off and look.

 

Is the choke closed???

Is there fuel visible in the small round sight glass on the front of the carb???

 

Test both #1 plugs by removing and putting an old plug in the end. Lay on a grounded surface and crank motor. Do both spark???

[Justice4kurt182]

its a '80 with the L20B, no janky dual ignition stuff. and yes #1 does spark.

[datzenmike]

Then you had half of what needed for an engine to run. Now confirm that you have gas in the carb and the choke is on.

 

Choke ON...

 

 

Choke NOT on...

 

.

[Justice4kurt182]

I'm not currently at the truck but i believe that it is on.

[datzenmike]

When you are check foe gas. This is the second thing needed to run.

[Justice4kurt182]

thanks for the speedy reply. the truck is at my parents place and I am currently not in town.  I will be sure to check for the gas in the carb. trying to start the truck with panther piss doesnt really make any difference.

[Robert]

^{Though gas and spark are needed, no argument there....BUT, they need to have dozens of other things accur exactly when theyre needed to accur....If the gas and spark are there, then your next check should be timing.  Check your chain and see if its not jumped.}