So I just finished making a Siamese 20/22r to fit into an 84 truck and I'm having a wicked carb issue.

Basically the secondary/choke barrel of the carb is DUMPING fuel into the motor. Imagine taking a super soaker loaded with gasoline and spraying it down the intake. That's what it's doing when it runs.

Surprisingly, there isn't a ton of smoke (mostly white smoke), and the engine runs decently, despite a considerable drop in power (maybe 50 horses) and an astoundingly horrific gas mileage. (2-3 mpg)

I've messed with the idle mixture screw, but even when I tighten the screw in all the way the engine still runs fine. This doesn't make any sense to me, it should be making the mixture completely lean, but the engine still runs fine and even continues to dump fuel in.

I'm thinking maybe the needly valve is messed up? The mixture screw itself is completely fine. The main vacuums are all hooked up (advance, choke, accelerator). Is there maybe something else I'm missing? Is my jet just messed up?

 

Whoa! Serious carb problems. I reccommend a full rebuild. Just my two cents.

 

I messed with it a bit more today with no avail. The secondary barrel is just dumping fuel in regardless of what I do on any of the screws. I found a used carb for pretty cheap, I might just go with that, unless there is something I'm overlooking.

 

I can't think of anything your missing. Probably something in the carb let go. Go with the used carb.

 

x2 on tring a different carb, sounds like yours is in need of a complete overhaul