Also here's a dumb question but the tank vent, where does it run? To the canister like modern vehicles or up the filler neck?

 

To the cannister. Little bitty thing.

 

Its probably not something you'd want to do then. Lots of wire pulling, fuses, mounting, sensors, looking for power sources/grounds, cutting fuel lines, etc. But once its installed and you have the right pressure its beeeeeeeautiful. Regulating it is not hard at all, just install a pressure regulator and gauge along the fuel line under the hood. You can see exactly what the PSI is coming through the line, and can adjust it.

 

You can do the latter using a mechanical pump. Summit sells their own brand of regulator that says Holley on it for about $25. I run one on Rusty.

 

I pulled the large vent hose off carb, can't blow through it at all so I let it removed. Took thin hose off canister, could blow through it a little yet still left it off. Cranked truck, issue got no better. Now depending on price I'm looking at picking up a new pump and filter if the local napa doesn't have the fuel pressure vacuum tester

 

It might be almost as cheap to just replace the pump instead of buying the tester. However, if the problem is associated with the pump but not actually the pump then it would persist. But, I can't think of a scenario where that was the case. The tank vent being plugged will only reduce fuel pressure, not increase it. The carb's vent isn't plugged as you tried several carbs inc a new one. There's nothing left but the pump to give high fuel pressure. Having said that, I've not seen a pump give too much pressure, although I've heard it can happen.

 

Me either but I've already thrown a bit of $$ at it so I new pump won't hurt. If that doesn't get it then I will resort to buying the tool and likely a regulator afterwards.

 

I think you are at a point where replacing the pump isn't "throwing" parts at it. Just the presence of fuel in the crankcase is enough to replace the pump. Keep the old pump and carefully dissect it and look for damage in the diaphragm. Sounds like you have more time than money.

 

Hopefully is isn't expensive, and no right now I have more money than time. Lol been working 7 days a week so it's hard to make time for my projects. Been trying to figure this particular issue out for months I can't wait til it's solved

 

Napa proline shows an Airtex pump #AFP 60330 for $30.95.........or Advance Auto same pump Airtex Part No. 60330 $22.41. I'm in Florida so your cost might different. The Napa pump isn't worth paying any extra for. Both are Airtex not as good as a Carter. Buy whatever is closest to you. Good luck.

 

I just fixed mine. I put my new PSI/vacuum tester on the pump and it read 8lbs, I adjusted it to 7 and it runs like a gem. No more volcano. I was considering trying a new carb there for a second......So I say it must be your pump.

 

Good to know. But yours is an electric pump - right?

 

One pound makes that much difference? Wow this is a whole different world from FI!

 

Yup. The float has to overcome the pressure of the float to close the needle against the seat. The more fuel pressure the further the float sinks in the fuel to get the needed force to close it. At some point it goes completely under and can't close the needle, which means fuel continues to come in faster than it is used. The result is that the fuel overflows into the engine and/or out the vent.

Each carb design varies on how much pressure it can handle. Edelbrock says no more than about 5 1/2 psi for its carbs, but Autolites can go higher.

 

In my opinion carb systems can be very sensitive and tend to be much more "individualized" so to speak. I would say 1 pound on his truck wont be the same as 1 pound on your truck. Lot of variables to consider most the condition of the secondary ignition as well intake manifold vacuum and even altitude and barometric pressure will have significant influence. Not always a hard and fast number to use, find what works go from there. Carb systems need tweaking. Take care.