I fought the carb and I WON!

First carburetor rebuild yesterday! (I know! I'm as excited as you are!)

The accelerator pump in my carburetor was a bit "weak" and the carb would spit if I tried to "stand on it" with out giving the vehicle due warning.

I bought a kit from carburetor-parts.com for my Rochester BV and away I went!

Cleaning and replacing stuff took me about an hour and I had it back on in no time flat.

And that's when the carb fought back.

The car was running like crap, it was harder than hell to start, would stall on hills when left to idle, and jumped like crazy if any sort of constant throttle was attempted.

I also noticed the bowl was leaking out the top gasket.

Long story short: I'm REALLY familiar with float adjustments now, as well as any sort of needle float valve seating, how to check the needle float valve to make sure it IS seating, and I can have that carb apart and back together in 2-minutes FLAT! In the end it was the new gasket that was pinning the floats down. Maaaaaaaan that threw me for a loop! I was beginning to wonder if I was EVER going to get this thing to run right again. Shoot, I almost went in there with gasket sealer (it's sitting right next to me as I type) but that little voice said "yo numb-nuts, how the hell is gas getting that high in the bowl in the first place, and you really want to risk getting that E36 M3 in your gas and potentially plugging one of these teeeeeny little holes?"

I love that voice sometimes.

Anyhoo, old gasket back on (old gasket is also much much thicker), timing set, idle and idle mixture adjusted, and she's as regular as my grandmother after prunes.

The bad news? There is still a bit of a miss. Might do a compression check. I'm beginning to wonder if the valve seats were ever replaced... I guess it'd be a little late for lead additives now.

Not a bad education for $20! but next time I'll just replace the accelerator pump seal and call it a day.

Good times,

-Bill

As regular as my grandmother after prunes, I'll have to remember that one

Now do a quadrajet, and tune it so that the secondaries come in smoothly without the signature "quadrabogggggg" that everyone thinks is normal...

Challenge accepted.

novaderrik wrote: Now do a quadrajet, and tune it so that the secondaries come in smoothly without the signature "quadrabogggggg" that everyone thinks is normal...

I may have spoke too soon

The test drive went great, but the ride home ended up being a bit "rough". I think I'm actually looking at a timing issue now though...

"The Carb Strikes Back!"

that's what you get for mocking the carb gods prematurely.

You posted your success before you tested it? The carb Gods are not happy. They're a cranky bunch.

tap it with a screwdriver handle..

If it's runs well cold, then gets rough, you might be running a little rich. Did you actually mess with any of the engine timing stuff?

Just a stab in the dark.

You are funny I grew up rebuilding carbs. It is that new fangled fuel injection that is a black art.

Is it wrong, that I built a megasquirt before I rebuilt a carb?

I didn't mess with my timing until after the rebuild. It seems to like 2-degrees less advance now though... was 8btdc is now 6btdc.

There were also more new gasket problems near the throttle plate, but I got those squared away. To answer MR2: It took a little longer to start when cold (and took more gas pedal pumps) and then was a bit "rough" at constant highway speeds. Warm start was also more difficult.

Right now it's running a lot smoother, although I'm really thinking I need to have a look at those valve seats. I bought a hydrometer for my garage as a trophy (and to help me adjust the idle mixture).

good times

Carbs are finicky , error prone devices. EFI FTW :)

Hungary Bill wrote: Is it wrong, that I built a megasquirt before I rebuilt a carb?

No, it's wrong that you regressed to rebuilding a carb after building a megasquirt. :)

In reply to novaderrik:

That has fixed the only "issue" that mikuni has had. One time a float was sticking and it would flood out immediately.

the other "issue" is that my engine is too small for my carb or I need a 2nd one.

I actually got rid of my megasquirt for my carb setup. I got tired of it not working ever. Sure its not efficient but its stupid simple and it works.

I fixed the carb issues with my truck by just getting a newer carb for it.

fidelity101 wrote: In reply to novaderrik: the other "issue" is that my engine is too small for my carb or I need a 2nd one.

You need a second engine?

It's back:

Return of the Carb!

Up till now I've been starting the engine and driving the car after carb work so the bowl was dry. I figured it was normal to have to crank on it forever to fill the bowl again. Today was the first time I actually shut it off and tried to restart. It takes about 30-45 seconds of cranking to get this puppy going again!

Car runs, drives, and idles fine, it just requires lots of cranking to start it once it's shut off. I'm thinking float adjustment is incorrect? The floats were set at 1-8/32" before the rebuild but after I did the rebuild I set them to 1-9/32 in accordance with the mfr's specs (lower setting/less fuel in bowl). I'm thinking I'm going to try setting them back at 1-8/32 (higher setting = more fuel in bowl).

For giggles I tried wacking the hell out of the carb with the screwdriver handle (I was pretty frustrated), no change but I sure felt a lot better!

(mixture screw is 2.5 turns out from bottom, idle speed is fine when it is running)

Good times,

-Bill

In reply to EvanB:

yes, or a 2nd carb. Maybe both

Hungary Bill wrote: For giggles I tried wacking the hell out of the carb with the screwdriver handle (I was pretty frustrated), no change but I sure felt a lot better!

Next step - switch to a 10 lb sledge.

jstein77 wrote:

Hungary Bill wrote: For giggles I tried wacking the hell out of the carb with the screwdriver handle (I was pretty frustrated), no change but I sure felt a lot better!

Next step - switch to a 10 lb sledge.

When using a hammer to fix something, one's level of happiness increases proportionally with the weight of the hammer.

amg_rx7 wrote:

jstein77 wrote:

Hungary Bill wrote: For giggles I tried wacking the hell out of the carb with the screwdriver handle (I was pretty frustrated), no change but I sure felt a lot better!

Next step - switch to a 10 lb sledge.

When using a hammer to fix something, one's level of happiness increases proportionally with the weight of the hammer.

(reaches for the 30lb sledge...)

Carbs are half voodoo, half black magic and half the devil. I stay away from them because anything that is 150% is bad juju.

Messed with the carb for about an hour. I adjusted the floats back to where they were BEFORE the rebuild and it quit idling and became harder than hell to start.

Lots of tail chasing followed as I adjusted the floats back to where they were when I got in there TODAY, then I tired to eye-ball the level based on the lines on the floats, and so on and such.

No joy

I had a state patrol inspection today (that's another thread in itself) so I said screw it and put on my "left-foot-braking shoes". Made the inspection and drove it home to make one last adjustment and still couldn't figure out for the life of me why the car wouldnt idle.

More float adjustments and head scratching followed.

Just as I needed to leave to pick up the kid from daycare I notice the fast idle stepper cam thingie that the idle adjustment screw rests on is installed 180 off (so the throttle plates were completely closed when I let off the gas).

Now installed correctly, the carb is back to my "baseline" (where I started the day today) and I can't test drive it because I don't have the car seat...

I'll work on it another time.

Someone needs to change this thread's title to "I fought the carb, and it let me think I won only to run me in circles, throw me completely through the roof, and pin me down in a stranglehold until I cried like a sissy girl, then it shot me with the other barrel, and it didn't even kiss my neck first".

find a way to put a holley on it after fighting with a quadrajet and motorcraft 4 barrel i swapped to holley and have found these to be the simplest carbs ever!

Ran the car today!

A bit long on the cold start, but otherwise ran durn near perfect.

I'm going to quit touching it now. I can deal with long cold starts (for the moment).

Maybe a stupid question, but I didn't see it mentioned. Is your choke working?