454 spits out carb at 20% or so throttle at low speed

[potent rodent]

from the looks of that plug it will not run right it will pop and crack, how did the rest of the plugs look like , have u done a compression test on the cyl the plug came out of

 

[WesN]

Possibly a cam lobe going away. Haven’t seen it for years but replaced many for popping out of carb back in the day when GM had its cam issue of wearing out lobes.

 

[Stumann666]

timing is at 8 degrees at idle. I'll look over the cap again. I'll also make sure my plug wires arent touching anything or each other.

With that RV cam, you might try bumping the timing a little more. Try 12 degrees.

 

[UNEAKMEDIA]

Main jet is .110". Main jet secondary is .107". Metering rod is .075" x .047". Orange stepup spring. Needle seat is .0935". I had some problems starting the other morning when it was real cold out. Heard some ticking coming from the engine bay when I was trying to start it so I reorganized all the plug wires so nothing is touching anything. I'm going to fire it up this morning and see if that helped. I'll also see if the 12 degrees timing helps.

 

[UNEAKMEDIA]

Oh and the cam has 6500 miles on it so I hope its not damaged already.

 

[85 Squarebody76]

Intake valve sticking ?

 

[Ichy62]

out of the carb not the exhaust. and sometimes it diesels when i turn it off. not so much after the rebuild. i'll have a chance to work on the truck this afternoon and i'll post the results. it sounds like a pop not really loud but it kills the engine for a split second and it continues to run.

Sounds alot like timing too retarded...5-10 static, 36 total is a good starting point. Retarded timing requires more throttle opening, which causes the dieseling...

 

[kapowsinWa]

Yep the timing is retarded.. advance it to 12 degrees