86 f 250

[bushanic]

this truck ran great until i let the crew start using it. had to replace the carb when i got it. new cats and ignition module. now it seems to be running really rough and i can see a light blues smoke from the tail pipe at idle and smell like gas and blackes when i give it some gas. This truck never did this before even with the old carb i replaced. i remember with a holly 4 barrel if the truck back fire through the carb it would mess it up is this the same with this 1 barrel cant recall the manufacture right now. thank for your advice.

[jonmark1985]

I didn't quite get all that

What kind of motor is in the truck? Is it a 4 barrel or a single barrel?

Check your timing, and make sure you don't have any broke vaccum lines.

[bushanic]

300 inline 6 with a single barrel carb.i did look for a broken vaccum line did not find
one but i will look again. the timing is good.

[jonmark1985]

i would bet your carb is loose, very common on the 300's, should be two bolts that hold it to the manifold if i remember right.

it uses a carter carb

[olddude]

also check the screws that go in from the bottom of carb. they hold top and bottom of carb. together.