Pontiac GTO Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hi, my Pontiac 428 800 double pumper spread-bore is leaking out the top castle looking post on the secondary. I was getting backfires until I filled up the primary bowl through the vent. It was running on the secondaries only I think. I took off the secondary bowl and cleaned it, but haven't started it yet. I took the secondary float out and shook it, it doesn't seem to have a leak. Any other ideas? Could that starve the primaries somehow? After I filled the primary bowl it ran great again, but had to sop up the leaking gas on the top of the secondary bowl. Thanks!
 

·
Registered
Joined
·
3,759 Posts
Hi, my Pontiac 428 800 double pumper spread-bore is leaking out the top castle looking post on the secondary. I was getting backfires until I filled up the primary bowl through the vent. It was running on the secondaries only I think. I took off the secondary bowl and cleaned it, but haven't started it yet. I took the secondary float out and shook it, it doesn't seem to have a leak. Any other ideas? Could that starve the primaries somehow? After I filled the primary bowl it ran great again, but had to sop up the leaking gas on the top of the secondary bowl. Thanks!
I would get a rebuild kit and simply go through the entire carb. Why waste your time chasing each little problem. You also want to ensure that you have a contemporary needle & seat assembly that is ethanol friendly. The older rubber tipped needle will deteriorate causing problems (if yours is of this type).

Your needle and seat assembly could be either stuck or have some form of blockage not allowing gas to fill the primary bowls. So rebuild it to freshen it up and set the floats to spec. Make sure none of the vent holes are plugged.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Thanks. I did all of that, rebuilt the whole thing. New floats didn't come with the kit. I will take primary bowl off to see if there may be a problem there, but I did clean out everything. I am only getting non-ethanol gas, octane boost and lead additive, and sometimes Stabil if it will sit.
Thanks
 

·
Registered
Joined
·
4 Posts
Discussion Starter #4
I took off the primary bowl and again cleaned everything out, filled up in the vent tube and then it ran fine again. I did put in an inline filter previously with sight glass.
I can now see some dirt specs in there, can that have clogged something in the primary and let only the secondary side fill up too much? The tank should probably be replaced, I drained it after sitting a long time and refilled it, but ran a bit without the inline filter, just the one in the carb. I am guessing dirt caused this. I think it is good again for now. Thanks
 
1 - 4 of 4 Posts
Top