1975 Ford F-250 with 390, auto transmission, RWD Camper Special
Must be very early 1975 because it still has points ignition.

Bought it and ran okay but was in need of tune-up. Here is what I replaced:

-Spark plugs and wires(Motorcraft with stock plug gap, same gap as old plugs)
-Distributor Cap and Rotor
-Cleaned point contacts and readjusted
-Fuel line and fuel filter
-Carburetor mounting gaskets
-Replaced vacuum lines and vacuum caps
-Cleaned carburetor (Edelbrock 1405, 600cfm)
-Valve cover gaskets and Header gaskets
-Cleaned Coil connections

It would start up fine before and idle fine, accelerate fine. Now it barely starts and if I try to give it gas it will puff air/fuel out the carburetor. If I spray starting fluid in, then it will start fine but when I touch the throttle it just dies and puffs air/fuel out the carb. Also saw smoke out the breather. I didn't touch the carb so it should still have the same settings. Here is what I checked:

-Checked that #1 was at TDC and was correct with the timing marks, also checked with the crank at about 10 degrees BTDC and the distributor rotor was at #1 spark plug wire contact.
-Checked the firing order and it's spot on. I didn't take the distributor out.
-Took the #1 plug out and it smelled like gas so it seems like too much fuel or weak spark.
-Checked over all connection and tested coil resistance and was in spec.

As I said it ran okay before and it should run the same if not better, I just replaced parts and didn't adjust anything on the carb or distributor. I was thinking maybe the points and condenser were to blame, so I might try replacing those just to be sure (condenser screw was actually loose when I first took the old distributor cap off). Any ideas? Any help is appreciated.

 

Hi,

Without seeing it, my first thought: Are the plug wires installed on the cap and to the correct plug in firing order, 1-5-4-2-6-3-7-8?

I agree, a quality set of points should replace what was in the distributor.

Mike

 

X2 on the firing order. Ford distributor turns counterclockwise. Make sure #1 plug wire is in the correct terminal on the distributor.
Bring #1 cylinder to TDC on the compression stroke and check and make sure the rotor is pointed to the terminal tower that the #1 plug wire goes to.
Just so you know, the #1 cylinder is passenger side front cylinder and the cylinders are numbered front to rear, passenger side 1-2-3-4 and drivers side 5-6-7-8.

Also, if you install a new set of points, the gap is .017" and be sure to clean the contacts. They used to have point cleaning files but I doubt anyone still knows what those are.
Get some fine emery cloth or sand paper. Fold it over so its rough on both sides, then run the paper between the point's contacts. This is to remove the oxidized coating that develops on the contacts when the points sit in stock. Next take some clean paper (a dollar bill is perfect) and run it between the contacts. This is to remove any grit left from the emery cloth. On last thing, most points come with a small capsule of grease. This is dist. cam lube. Use a very small amount to lube the dist cam and put a small amount on the point rubbing block. It goes on the leading edge side (the side towards rotation). If you don't use the grease, the rubbing block will wear quickly, closing up the point gap.

 

Thank you for the quick replies. I just figured it out, long story short always check new parts before installing. I was looking at the distributor rotor and the new one was about an 1/8"-1/16" shorter. I put the old rotor back in and runs fine now. This was causing poor spark which makes sense. Damn O'reilly's

 

Glad you found it.
BTW welcome to FTE. Lots of good, knowledgeable people here (and a couple of grouches ).

 

Thank you. I was a member years ago, but I couldn't remember my username or password so I had to start fresh.