Need Your Experience and Advice

[rn2fine]

On my 350 equipped 72 I am having two problems (listed below). I am looking for advice from those with experience on how to deal with the problems.

1) Starting approximately 1 week ago the engine began to diesel (continue running after I turned it off) big time. It is a 350 with 20,000 miles, Edelbrock heads, Edelbrock carb, and HEI. Runs great, engine temp is great (180), its not overheating, running premium gas, and timing is per specs. I also have an O2 sensor and gauge and mixture is good. Running Bosch +4 platinum plugs and have since engine was new. I called a friend and he said it may be a stuck float in the carb that is leaking fuel into the manifold after shut down. Any thoughts?

2) WHen I turn my air conditioning on I, and after it is on for about 5 minutes, I begin to smell something burning in the cab, coming from the dash area. There is a large red wire that comes out from the back of the ignition swith and I felt it when I smelled something burning. It was really hot. Too hot to touch for more than a second. When the AC is not running the wire is cool. AC blower fan is running great with no signs of problems. A friend of mine states that I should replace ignition switch. Any thoughts?

Thanks

[70clone]

1) the only thing i know that will make an engine diesel like that is carbon buildup on the pistons basically the carbon is staying red hot and the engine has enough rotation to suck fuel from the carb into the cylinder causing it to detonate as if the spark plug was sparking when myne started this i went and bought a bottle of seafoam and put 1/3 pint of it it through the brake booster vacuum line as the motor was running shut it off and let it set for 5-10 minutes and presto the problem was gone. to me if it was a stuck float you would be able to take the air filter off and watch it after shutdown and it would prolly be flooded every time you went to start it . but ne who the seafoam worked for me cant say thats your problem just my 2 cents.

ps; it will smoke alot if you have alot of carbon buildup in there but dont worry it goes away the seafoam basically makes the carbon buildup release and the only way to get rid of it is through the exhaust lots of smoke it goes away after you drive it down the road


2) i would check the wire and make sure it has rubbed up against something metal and got grounded out because this causes fires and we dont want that. The only other thing i could think of is the wire isnt big enough to power the fan

[boundstaffpress]

Ususally you can stop the dieseling by making the carb close all the way this keeps oxygen from being able to reach the hot piston. Fuel is drawn into the carb with the oxygen, I doubt the float is stuck.

I'd look for a ground short on your compressor switch wire and your fan wire.

[Wrenchbender Ret]

Vacuum leaks or idle speed to fast will cause run on. Lower the idle speed as much as you can & still be comfortable.
You need a new connector on the back of the ign. switch. You can buy a pigtail for that that has a few inches of new wire that you splice to the old ones. If it is factory air The high blower should go through a relay. It pulls to much current for the switch.