I have a 77 RN, stock carb and emissions. At idle I can see a boat load of fuel dribbling into the carb from the primary jets. The truck runs really, really rich and idles like crap. My 76 Corolla does not do this so something is amiss.

Sorry, I don't know how to embed on this site - Here's some video I took of the problem:

Aisan carb on 20R engine, 1977 Toyota Truck - YouTube

Any ideas of what's going on?

Thanks!

 

First thing that popped into my mind was float adjustment. I'm guessing it's too high. It should pour like that unless you're pumping the accelerator.

Wiki carby diagram

 

Thanks for the reply...I found the problem. It was a bad aux accel pump diaphragm.

Since it seemed that there was not enough vacuum to operate the power piston which would leave the power valve in the "cold" setting, I used my vacuum pump to check other various fittings and vac solenoids. I checked the thermo vacuum switch on the intake and some "fluid" got sucked into my vacuum pump. At first I thought it was anti-freeze so thinking that this was the culprit I got busy looking for a replacement. Not finding any replacements available I started fiddling around with other stuff, one of which was the vac diaphragm. Well that one also had some strange fluid coming out when I put vacuum on it. I tried to smell it and I couldn't smell a thing. I did notice that it was evaporating quite nicely so I concluded that my sense of smell was shot from all the gas and that it was gasoline. I replaced the diaphragm and lo and behold no more fuel dribbling in.

The truck runs well now but it still won't pass smog. The CO level is too high. I tried setting the timing to 10 - 12 BTDC but the level was still high. Was I supposed to go the other was to reduce my CO? Factory setting is 8 degrees BTDC.