1981 F100 Keeps running

larbec7 · 08-26-2009, 07:37 PM

My son has a 1981 V6 (I think 4.9) and it would not run at all. He changed the spark plugs, plug wires, distributor and started the truck. He drove it down the road and when he came back home it would not stop running. I think it is carbon build up but did not have any carburetor cleaner (I will get some tomorrow) what would cause the truck to continue to run even after we turn the ignition switch off? We even pulled the spark plug wires off and it still ran.
We had to put a shirt over the carburetor to get it to stop

Help please!

stumpuller454 · 08-26-2009, 07:52 PM

run a can of seafoam through a tank of gas. and change the ff after, if its a cheap ff change it prior to seafoam, then change it after the tank. must be a ton of buildup in there,another trick i`ve heard of is to get the engine hot, rev it up to about 3k rpm and then proced to spray water down the carb (from a spray bottle) the water will enter the hot combustion chamber and expand very rapidly blasting the carbon off of everything, again i heard this works but have never tried it. my dad said he used to do it once or twice a year to his old 79 chevy truck.

BernieB · 08-26-2009, 08:08 PM

I've done the water spray myself on badly carboned up engines, and it does work beautifully.

leolkfrm · 08-26-2009, 08:09 PM

i used to add ice to the bottle, the colder the water the better the job. Delco used to make a chamber cleaner which worked well but i don't know if seafoam is the same thing

Case 7230 · 08-27-2009, 03:03 AM

Did you fit the correct spark plugs? Did you check the ignition timing?

larbec7 · 08-27-2009, 03:17 AM

I will try the seaform and water and see if it does the trick.

I do have the right spark plugs, cap and ignition timing is good

bradrhale · 08-27-2009, 07:54 AM

major contributor to carboned up engines >>> dirty air filters.

08-26-2009, 07:37 PM	#1
larbec7 Full Member Join Date: May 2007 Posts: 47	1981 F100 Keeps running My son has a 1981 V6 (I think 4.9) and it would not run at all. He changed the spark plugs, plug wires, distributor and started the truck. He drove it down the road and when he came back home it would not stop running. I think it is carbon build up but did not have any carburetor cleaner (I will get some tomorrow) what would cause the truck to continue to run even after we turn the ignition switch off? We even pulled the spark plug wires off and it still ran. We had to put a shirt over the carburetor to get it to stop Help please!

08-26-2009, 07:52 PM	#2
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	run a can of seafoam through a tank of gas. and change the ff after, if its a cheap ff change it prior to seafoam, then change it after the tank. must be a ton of buildup in there,another trick i`ve heard of is to get the engine hot, rev it up to about 3k rpm and then proced to spray water down the carb (from a spray bottle) the water will enter the hot combustion chamber and expand very rapidly blasting the carbon off of everything, again i heard this works but have never tried it. my dad said he used to do it once or twice a year to his old 79 chevy truck. __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

08-26-2009, 08:08 PM	#3
BernieB Senior Member Join Date: Jul 2009 Location: Fredericksburg, VA Posts: 1,910	I've done the water spray myself on badly carboned up engines, and it does work beautifully. __________________ If the guys who design 'em had to take one home, use it every day for 2 years, and do all the maint and repairs themselves, cars would have a button on the dash to change the oil, filters & plugs.

08-26-2009, 08:09 PM	#4
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	i used to add ice to the bottle, the colder the water the better the job. Delco used to make a chamber cleaner which worked well but i don't know if seafoam is the same thing __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

08-27-2009, 03:17 AM	#6
larbec7 Full Member Join Date: May 2007 Posts: 47	Thanks I will try the seaform and water and see if it does the trick. I do have the right spark plugs, cap and ignition timing is good Last edited by larbec7; 08-27-2009 at 03:26 AM. Reason: want to get automatic email

08-27-2009, 03:03 AM	#5
Case 7230 Senior Member Join Date: Dec 2007 Posts: 547	Did you fit the correct spark plugs? Did you check the ignition timing?

08-27-2009, 07:54 AM	#7
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	major contributor to carboned up engines >>> dirty air filters.

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