89 Camaro with swapped 305 (was V6), Edelbrock performer, Holley 4 barrel. Was running fine, til fuel pump died. Installed Holley blue with reg & gauge. Have 5psi going to carb, have gas squirting out of carb input (where fuel hose hooks up). Car wont start. Prior to the new Holley pump, I had a installed a new Master in-tank pump like the one that was working before (supposedly 18 psi, 35gph). Also had a Mallory 4309 reg with the old and new in-tank pumps. New in-tank pump squirted LOTS of gas out at the fuel input to the carb. Couldnt get the Mallory apart to install a gauge. Gave up on the in-tank pump (cut the elec wire and hooked up new Holley blue) and the Mallory. Now I wonder how the carb works. I dont know anything about carbs. Where is the gas supposed to go, and how do I tell if something is broken, out of whack, etc? A real basic explanation would be helpful, or suggestions about which books or manuals are good. Thanks!

 

I'm not quite sure what you're asking...can you be more specific? Look around on summitracing.com for books on carbs, especially one specific to your model, that's a good place to start. Also, if you're going to start tuning cars, you absolutely need a fuel pressure guage. There are several threads written on this. Just do a search and you should find them.

 

Thanks. I bought a Chilton book about carbs. I have the Holley 4160 model. I have a fuel pressure gauge (between the regulator and carb) and it shows 5 psi. I dont think I'm getting any gas into the main part of the carb, since gas spurts out of the input connection, and I dont see any gas down in the carb. Seems like the next thing to check is the needle valve and seat, and floats. If they are stuck or damaged, then the inlet valve may be closed, preventing gas from going into the bowls and so forth. As I understand the book's description, gas should be going into both bowls and remain until vacuum pulls the gas thru the metering block (based on load, choke, etc). I will see if I can get the inlet connection off and see if something is blocking the input into the bowls.

 

Now you shouldn't have any fuel squirting out of that fitting period, even it the inlet is clogged. It's going to close up once the bowls are full anyways. You might need to fix that fitting, cause your probably losing to much pressure at that fitting.

But certainly a blocked inlet isn't going to fill the bowls, but you can't have fuel leaks anywhere before it. esp squirting fuel yikesss.

Ron

 

Oh yea, You can use an empty CLEAN mustard bottle or what ever to prime the carb with gas. Just shot down into the bowl vents, and It make starting after a jet change or new install much more easier.

Ron

 

Thanks. I took the banjo inlet fitting off and inspected the screen filter in the carb inlet. Maybe the holes in the fitting and the screw weren't lined up. Also cut off the end of the hose and tightened the clamp. presto! no more leaks there. Took apart the main float bowl and saw no dirt or problems. re-assembled. car wont start. poured gas in the bore, still no start. sprayed starting fluid in, still no start. noticed mist blowing up out of carb. Called my brother, says timing is off, spark not igniting gas at the right moment. Turned distrib a bit, car starts! Now I'm working on the float level adjustment and idle setting. It's down to 5 degrees here...will try adjustments when it gets warmer.

 

i'd suggest you get a timing light n verify the correct timing before you go driving it...

keep those piston rings aslong as u can =]