Engine/Carb Problem

kmm5612 · 05-30-2010, 12:24:58 PM

I pulled my carburetor off earlier this year to clean it and put in new gaskets. Before this, the car ran fine except for a small timing issue, which I expected to fix when I put the carb back on. Recently, I went to reinstall it. I filled the float bowls, hooked up all the hosed correctly (I triple checked), and went to start the engine.

And got nothing. The starter motor runs, the engine cranks, but only a couple cylinders fire randomly until I release the key. It never fully gets running. I checked the fuel line, the fuel filter, the fuel inlet on the carb, everything is clear. I reset the carb to factory pin settings, and still had the same issue. I loosened the fuel line to instigate a fuel leak, just to make sure there was fuel pressure reaching the carb, and there was plenty.

Any ideas where to start? The car ran fine before and somewhat fires now, so I don't think the plugs are an issue. I'm thinking it is a small issue I'm overlooking due to being inexperienced, but I can't seem to figure it out.

It is a Holley 600cfm carb, hooked to an eddy intake manifold on a 350. The car is a 1978, if it makes a difference. Thanks for the help!

zekefreak · 05-30-2010, 12:31:24 PM

Sounds to me like its flooded. Hold the accelerator pedal to the floor and crank it again. Do not pump the pedal. Maybe pull a plug and see if its wet. If so, then that would support my theory.

kmm5612 · 05-31-2010, 09:18:42 AM

I tried de-flooding the engine, and while the pedal was to the floor the cylinders were firing a lot more, sounded almost like a startup. However, I released the key and it died again. I went to try it for a second time, and NONE of the cylinders fired, only the engine cranked.

I changed out all the plugs, just to be on the safe side, but it didn't make a difference.

zekefreak · 05-31-2010, 10:50:19 AM

Nothing else was touched when you pulled the carb? Then I would think the problem is inside the carb. Are the gaskets the correct replacements? Were any installed upside down? Are the floats adjusted properly?

kmm5612 · 05-31-2010, 07:36:58 PM

I touched nothing else when I pulled the carb, even the intake manifold remained on and was sealed. I filled the floats to factory specs (just below the sight plug) before installation. I have no idea what to look for...

zekefreak · 05-31-2010, 10:21:51 PM

Without touching the throttle, spray some starting fluid in the carb or air cleaner. Crank the engine and see if it will start. If it does, keep spraying little shots until the engine runs on its own. If this doesn't work I think you should pull the carb and tear it apart again and see if there's something wrong.

BTW, I'm assuming the choke is open. If it isn't, manually hold it open or stick a screwdriver in there to hold it open and try again.

kmm5612 · 06-02-2010, 04:16:23 PM

So I finally got the car to idle, had to back the mixture screws out a half turn each. The problem now is, the SLIGHTEST opening of the throttle or pressing the gas pedal causes an immediate stall. No stumble or anything, just immediately dies. Any idea what the issue is now?

mrdragster1970 · 06-02-2010, 04:22:08 PM

.

I like to make sure all 8 are firing before changing anything.
It takes very little time and you might catch something.
Use your light, and check each wire.

When you changed the plugs, were they all similar??

.

kmm5612 · 06-02-2010, 04:25:29 PM

yes, plugs were nearly identical to what came out, I also double checked with the store attendant to make sure they fit a 78 z28.

zekefreak · 06-02-2010, 04:41:05 PM

Quote:

Originally Posted by kmm5612

So I finally got the car to idle, had to back the mixture screws out a half turn each. The problem now is, the SLIGHTEST opening of the throttle or pressing the gas pedal causes an immediate stall. No stumble or anything, just immediately dies. Any idea what the issue is now?

Sounds like the squirters aren't working. Make sure you hooked up the accelerator pump rod/lever and when you open the throttle (with the engine off) look inside the carb to see if it is squirting gas. If not then thats the problem.

kmm5612 · 06-02-2010, 04:53:39 PM

Just double checked the squirters, held the throttle open for a moment and they shot fuel down into the carb. It looks like some puddled on the throttle plates below the squirters, could this be an indication of a problem with the throttle plates opening? If so, can they be adjusted and/or how do I go about changing their settings?

Again, the car does idle now, so it must be getting at least some amount of fuel and air. That's why I'm not sure about the throttle plates.

Also - thanks for the suggestions thus far, they've been a great help!

mrdragster1970 · 06-02-2010, 04:56:42 PM

.

I meant the coloring, sorry. I assumed you used the proper plugs.

.

kmm5612 · 06-02-2010, 05:00:09 PM

Quote:

Originally Posted by mrdragster1970

.

I meant the coloring, sorry. I assumed you used the proper plugs.

.

I'm not sure what you mean by coloring, coloring of the plugs? They were the same color as the ones I removed, if that's what you mean.

Sorry, pretty new to this in-depth engine stuff!