crummy idle

[NAM VET]

Always something, I had a small leak under my coolant elbow, so wanting to replace my defective 180 OEM T stat, installed a new version of a 160, and temps are fine. But now my engine won' idle, it just slowly dies. I have a Facet electric 24 V pump, but the pressure at my fuel pressure regulator was erratic and too low, so replaced the regulator with $200 Aeromotive, 2-5 PSI one. But my fuel pressures were still way low, and noted my clear Wix fuel filter, just before the regulator was almost dry so removed the fuel filter, plumbed the gas line to the regulator then to the carb, and fuel pressure now fine at about 3.5 psi. I did have to put some new 5/16 hoses on. I just replaced the fuel filter in the Facet, it wasn't very clogged.

But now my truck won't idle. Removed and blew out the inlet needle valve, triangular one with the Viton tip, looked fine, no debris, then found my idle screw was about four turns + out, so removed, blew it out, and re-set to one tun out. Still slowly dies at idle, exhaust is clear, no smoke. Pulled #1 plug, fine, still 120 psi compression. The engine doesn't miss, or skip a beat, just slowly dies at idle. Just took it out for a test drive, and seemed to lack "gas" when accelerating.

Background, my carb and much of my truck was rebuilt by Charles about three years, ago and I have never touched the insides since, so no reason to think the float level is off. I run only non-ethanol. The bad idle is just happening today, even with low fuel pressure, it would idle fine before,.

The only thing I can think of is some bit of fuel hose or such got into the carb, or perhaps from the fiberglass insulation of the inside of the fuel line insulator hose when I pushed the fuel line thru it. And if you guys suggest taking off the carb bowl cover, I will get some new gaskets and do that.

If a bit of fiberglass or such got into the carb where is the most likely place to look for it?

Hal

[RCrombie]

In my experience, debris from fuel lines etc tends to jam the needle open and cause severe flooding.
I wonder from your description if maybe you didn’t bump your distributor when you were working under the hood, and now your advance is off.
Usually a starving engine will idle, and then hiccups and bucks when it is asked to move a load.
Just my 2 cents.

Rob

[Cal_Gary]

I recall optimal pump pressure should be around 4 to 4.5 PSI. I wouldn't think the float setting changed; however mine has a VERY cantankerous setting-a hair off either way starves or floods the carb.
Gary

[NAM VET]

I have fussed with a miserable idle for near ten days. My problem was first, an erratic Facet pump pressure, usually low, sometimes way too high. Simple, put on a new 4-5 psi 24 V Facet, about $95 from Pegasus Racing. But having already dinked around with my carb and seat (the triangular viton tipped needle and seat), my truck just wouldn't idle at all, it would only sort run at 1200 RPM or more. Exhaust was not smoky or gassy.

Put in a mew $200 Aeromotive low pressure regulator, new rubber lines, moved fuel filter to a metal one just before the Facet back in the rear,. The new Aeromotive is for 1-5 psi carbs, and with this one, and the now good Facet, my pressure is a rock steady 3.5 psi.

But an awful idle, so pulled off the top of the carb bowl, re-set the float level with my gage (more on that later), and buttoned it up and it was no better. Then just a few minutes ago, realized that I have been installing my needle Backwards in the seat! So pulled off the carb bowl cover, getting better at it now, reset it correctly and in a few minutes, my truck once again purrs like a kitten.

While the original problem was the Facet, my dumb mistake was the needle in backwards. But all good now, and I am so much relieved.

I am worn out from bending over my engine for the past few hours.

All the best, guys, And Charles T spent quite a bit of time with me on this with his suggestions.

Hal