I swear Satan himself worked for Rochester and shat out each of these carbs after consuming the soul of an orphan with a side of horseradish. Quick background, you can skip past this if you don't like to read. My '52 Ford has a 400 Chevy with a 2 barrel Rochester on it which gave me nothing but problems since I got it. Leaked when I got it, had it rebuilt by two different people and had the top off of it 15 times myself trying to figure out why it seemed like the float constantly stuck. Tried 3 different floats, 2 different needles, shitloads of adjustment. I asked about it here on the HAMB and this is the thread I started then, http://www.jalopyjournal.com/forum/...hester-2-barrel-float-needle-sticking.718828/ And here's the car, since everyone likes pictures. If you read that thread, you'll see that most of the advice I got was that my fuel pressure was too high, and I thought I had eliminated that as a possibility with a Mr Gasket type adjustable fuel pressure regulator. A friend of mine went through that carb and we got it working for a short trip around town, but I've been so scared of this thing acting up again, I haven't driven it in 2 years. Now the same demons are back to haunt me, this time on a '58 Chevy. Got this nothing-special Belair with a '69 350 and another Rochester 2-jet on it (2GV). A friend of mine went through the car and we got it together and running but with carb leaking problems. Wouldn't idle well, felt like a vacuum leak, and carb leaked gas on the intake. Looked like the carb was leaking out of the gaskets, I got a gasket kit and figured I'd just replace the base and top gaskets and clean the float bowl out good. Float bowl had a bit of dried up crust at the bottom but pretty minor, inside of the carb looked real nice otherwise, looks like a recent rebuild with a new accelerator pump and other hardware, has a poly float in it. I did notice the old top gasket was deformed on one side, thought that might be the issue. Put it back together with new gaskets and all cleaned up, tried to start, gas everywhere. My first thought is the needle is stuck, take it back off and pull the top off, needle looks fine, try again, still gas everywhere, take it apart again, needle still opening and closing fine, float itself seems good, not heavy, read all about how to adjust float levels, re-set the float to the correct specs (it was off by some), try again, still gas everywhere, and I now notice that after it's shut off, gas is dripping out of the venturis into the intake. This is the carb on the engine, in case that matters. So I'm right back to this same issue. Everything I've read says the two things that would cause this are the needle/float sticking, or too much fuel pressure. The float and needle of both carbs seems to work just fine, and I always figured the fuel pressure thing was BS since they both run a stock looking mechanical pump and my Mr Gasket regulator didn't do shit on the last car. But NOW I've read that those Mr G. regulators don't work for shit and I'm starting to wonder if the issue on this car AND my other car was fuel pressure all along. So here are my questions, and any help or experience is appreciated more than I can ever say. 1. Would a stock looking SBC mechanical fuel pump put out more fuel pressure than this carb needs to run? 2. How much fuel pressure is optimal for these little Rottenchesters, and how much more would it really take to make it react like this? 3. Are those Mr G. regulators really that unreliable or intermittent? 4. What would be the ideal, adjustable fuel pressure regulator to try on this car, preferably with a gauge? (recommendations with a link on where to buy one would really be great here, eBay lists like 1700 "adjustable fuel pressure regulators" and most show 0-160 psi, while I'm looking to fine tune between 3 and 4 probably, so not ideal). 5. The little tiny wire that hooks over the edge of the float for the needle seems really precarious, it doesn't go through a hole or anything. Should it bug me as much as it does, even though it seems to work? 6. Is there something else obvious that I am not even thinking of? I'm a horrible mechanic and easily frustrated by shit like this, I might be overlooking something easy, and I feel like this should not be as difficult as I'm making it. I apologize about how wordy I've gotten on this simple question but my '52 hasn't been out in years even though it's an otherwise nice finished, painted and upholstered car, and now I'm ready to set my '58 project on fire and push it into the river. Please help.
Have been researching for the last hour and a half, have read a LOT of instances of Chevy mech. fuel pumps making 7-15 psi! Apparently they are not well regulated. Have also read that the Rochesters like between 3 and 4.5 psi and that the Mr G style regulators are bullshit. Looking into the best regulators now, would love suggestions on that if anyone has any.
Holley makes a low pressure fuel regulator (12-804) that will work. I used one on a 54 Corvette to cut the fuel pressure on it back to 2 lbs while I was working on the side draft carbs on it. Worked like a champ. BTW, I've seen several of the dial style regulators come apart and pour gas out of them. Not good.
I can't help with the fuel regulator because I don't use one. I have a 283 with a mechanical fuel pump and a 2gc. It looks like you are missing a choke in your picture. Are you certain that the carb is correctly rebuilt?
Choke plate is on there, no choke or linkage hooked up yet, wasn't going to bother with it if I can't get this leak issue fixed, unless the choke would cause these issues, although I don't know how? I'm not a great mechanic and it's very possible this carb isn't rebuilt or set up right, although I feel like I've researched it pretty well.
Hey I know this sound stupid, but have you tried to crank it over with the top of the carb off? Just light presure on the needle and a buddy at the ignition. Maybe even pull of the terminal 1 for your coil(trigger ), better safe then sorry. Just for the purpose of illimination of the needle valve and or presure as you trouble.
The needle is in the top of the Rochester carb, not sure how that would work, although I'd totally try it. I'm currently checking out pressure regulators with gauges and I've bought complete good running 350 engines for less than what some of these regulators cost. What the fuck. I know quality isn't cheap, but is a decent adjustable regulator and a gauge really going to cost me over $100?
Don't get frustrated, this stuff is easy. Universal trouble shooting absolutes. 1. Verify the input. 2. Verify the out put. 3. Only The biggest problem generally shows up first, there may be more. 4 Dont fix symptoms, find and fix the problem. If you're fuel pressure is good, yes you'll need to verify that by measuring and knowing the required pressure the carb was designed to have. And the carb is slobbering fuel anyway. The desired out put would be a float bowl that holds fuel at the correct level. The needle and seat, float and float level and bowl is where you need to look for the problem. The needle valves wear, the Viton tips rot, the seats wear, it doesn't have to be a stuck float. There's also a chance that someone before you installed the wrong parts. A stock pump, match pump year to carb year should be fine, but until you measure the pressure you can't intelligently do much.
Another issue I seem to be having is the adjustable regulators all seem to have a range of 1-4 or 5-9 PSI, it's in the middle of those two ranges that I want to be. Can't find any exact pressure specs for this carb, lots of suggestions but kinda all over the board. A gauge sounds like a must, see where we're at and go from there. I really appreciate the feedback so far.
Have you put a gauge on the pump outlet side to see what it is actually putting out? I have had a couple that were wonky put out 15 lbs. normal is 4-5. Also make sure the float isn't hanging up on anything inside the bowl.
I guess measuring the fuel pressure first is the only way that you would know if you need to regulate it.
This is important...make sure you have a stock bronze fuel filter installed correctly with spring and gasket in the inlet of the carb, even if you have another fuel filter installed elsewhere...chevy engineers put it there for a reason...it blocks a little of the fuel pressure.
don't know why you see the need for a regulator , GM fuel pumps are internally regulated and has been used on millions of stock motors without the need of a external regulator . and unless you run a return line to the tank a external regulator still creep from the dead head pressure . the fuel pump should have only one outlet , if it has a small tube besides the block thats the wrong pump and will be a higher pressure as thats a emissions- A/C fuel pump and uses a higher pressure because it has a bypass back to the tank and it helps keeping the fuel from perculating when shut down hot and higher operating temps . this has caused many headache on older cars were people think a pump is a pump , the 4 bbl pump is a higher pressure /volume pump and will often blow the needle off the seat on a 2 bbl . many pontiac guys have problems when using these with 2bbls . one check your fuel lines as they are supposed to be 1" from any metal surface and away from the water pump or heater/cooling hoses, exhaust manifold and the water crossover area of the manifold , change it to steel , rubber holds heat and when the motor is shut down it will start to boil in the line , also get rid of the fire starter plastic fuel filter, the factory one behind the nut is more than sufficent and could he plugged with crap and bypassing it to the needle seat holding it open ( seen this more than once ) . and replace it with the brass sintered style one not the paper ones as ethanol will mess them up plus people crush them installing them . ( get it from http://quadrajetparts.com/ they are great for parts)
In your post you said you had a poly float, I assume you mean one like this- I have had this kind of float go bad and the needle valve will not seal off properly. By going bad I mean they absorb something( I'm not sure what) from the gas and lose their buoyancy. You can't tell simply by looking at it although there may appear to be some stains on it. I have ran into this problem twice and after replacing the float the problem was solved. I would replace it with a brass float considering todays crappy gas.
Its is always a good ideer to dump it in water or fuel and check float. And pulling the lid of a carb and holding the needle closed is an simple way to check if the pump gives to high pressure, or the seat is bad. I don it with my Dellortos, you just leave the inlet hose (fuel) on, lift the lit with float on and put a finger on the needle. Then your buddy cranks it over and this gives a good diagnose. As stated before.
them poly floats are a pain in the ..... if you damage or if its damaged , the outside surface they tend to melt from gas additives and loose buoyancy and overfill . we used to cut them to change them but you had to epoxy them up otherwise you had a empty shell in a few weeks , get a new float and make it a brass one .
I doubt the choke is the issue but when I saw it missing I assumed it wasn't set up correctly. I would get a gauge and a brass float like other have said.
BAM! Now we're getting somewhere... Symptoms are your friend. They'll help you find the problem that you'll need to repair.
Holley regulator will work well however you shouldn't need it. As above get the correct FP and make sure the sintered metal (bronze) filter and spring is in place. There have been millions of these things produced and it ain't rocket science...
I really appreciate all the response, I'm thinking with a much clearer head now. I will be buying an inline fuel pressure gauge which will be good to have anyway, and tomorrow I'm going to check on that metal filter to see if there's one in the car and if it's clear. I will also consider all the other suggestions I've been given, but I figure that's the best place to start. I'll report back on what I find.
sqau on the factory filter if its in there more than likely its full of snot , they are extrememly hard to tell if they are clear or not , its one of them items , if you haven't replaced it then replace it to make sure and write the milage and date down with a sharpie on the radiator support or somewhere you will not loose it .
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