Won't start -- Q-jet issues?

[Stocker]

Old faithful has finally failed me.... was my DD before I retired, and now it often sits for several days before I fire it up. A couple weeks ago it took forever to start -- cranked over OK and stumbled a few times (I thought I may have flooded it) but then it ran OK, and last week it started & ran OK.

Tried starting it a couple days ago (and again this morning) and it still cranks, but no vrooom vrooom type noises, nary a pop or stumble. Verified power to the HEI, and threw the timing light on #1 and get good flashes from it. Pulled the fuel line off the carb & cranked it.... got good flow coming from the fuel line.

What I don't seem to have is gas in the carb, but I'm not sure how to prove it. After several seconds of cranking, the float chamber should be full (right?) but when I look down through the primaries and operate the throttle, I don't see any fuel squirting inside the bores.

Thanks for any help, I'm kind of at a loss right now. I posted here for more views than the Engine & Drivetrain section... if the mods would be kind enough to leave it here, thanks.

Is there anything I can do besides pulling the carb off and taking it to someone who can go through it? I'm not at all comfortable with disassembling a q-jet.

[ChevLoRay]

Without disassembling it, you can still remove it and look at the throttle plate (base) and see if the two metal plugs are leaking. It is common for them to leak, which allows the float bowl to empty out into your intake, creating the flooded condition. Also, that excess fuel will wash the oil from your cylinder walls and dilute your crankcase oil.

If that is the case, and I'll be surprised if it isn't, then you'll know why it is acting like it is.

Go to www.edelbrock.com and they should have a technical help section. They used to sell a Q-Jet and you should be able to find some suggestions. I'm also sure that there are other websites that have lots of info on those carbs, including pix and drawings. Q-Jets aren't as complicated as we're led to believe. If you take it off, remove the top and lay it aside without turning the idle air screws. Pay attention to any check balls that are in it. You should have a small magnet handy to pull them (may only be one) out. Set it aside, too, and remember where it came from. Take pix before removing it. When you have that done, there shouldn't be anything that can fall out. Turn it over and you can remove the base plate. When you do, you will see the two plugs in the bottom of the bowls. New plugs include o-rings. Tap the plugs into place. NAPA used to sell the plugs and a dense foam piece that fits into the recess of the base plate. That foam is there to keep the plugs in place. Put the base back on, turn it over and reinstall the check ball(s) and then the top. Make sure the linkages are where they should be and you should be ready to install a new fuel filter and try it out when it is back on with a new gasket.

[cdowns]

Qjet carbs have the fuel filter inside the carb inlet

[Wrenchbender Ret]

Like Downs says. There is a small fuel filter in the fitting behind the fuel inlet line. Check that. If it is OK & You dont get any gas when you work the throttle you will need to get the carb o-hauled. Its not a good idea to get one of the over the counter remans. Most of them are not right. If you are brave & go that way DONT turn your old one in till you are satisfied with the replacement. It is best to find an old timer that can o-haul it for you. There is a lot of info & books out there on rebuilding them, but only you know your limitations.

[Stocker]

Yep, pulled the porous bronze filter out of the carb inlet when I checked fuel flow & pressure (pegged my 6# pressure gauge). Blew air through the filter.... no indication of it being plugged or contaminated.

[MagmaJct]

If it's flooding you should smell the gasoline, it's often strong. If the wind is too stiff to smell it, pulling and inspecting a spark plug will give you signs whether it's flooding or not.

However, if the problem is lack of fuel, it's possible the float needle has become stuck and it's not letting any fuel in. Fuel turns rancid (my term) if left to sit too long. It's possible it has caused the needle to stick. Good luck! Be safe.

[Pont406]

Bad accelerator pump. Spray some carb cleaner and see if it will start.

[Stocker]

My sniffer isn't the best (life-long allergies, sinusitis, chronic rhinitis, and a deviated septum -- other than that it's all good ) and I can't rely on it to smell gasoline.... might try pulling a plug tomorrow.

Fuel is relatively fresh, though.... made a few woodcutting trips earlier and had to fill up. I also tried rapping on the carb with a wrench in case of a sticking needle, but no help. Might be stuck anyway...

If I don't have any carb cleaner handy, I'll pick up a can in the morning -- or starting fluid.

If that fails, I'll start looking for a local carb guy. The last guy to rebuild it here has long since left the area. Even with ChevLoRay's words of encouragement (and the diagrams in my Clymer manual), I'm not quite willing to tear into it myself.

I appreciate everyone's advice -- I'll update this thread as things progress.

[cpisani70@aol.com]

I had similar problem, mine was a sticky float would crank and not start if I tapped the area of the float you could hear it drop and then it would fire right up. Ran it like that for a week till I bought a new brass float now it works fine. Just my 2 cents!
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[bmfm64]

Poor some gas in the carb and see if it starts.... If it does, have the carb rebuilt.
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[konasummit]

Originally Posted by bmfm64

Poor some gas in the carb and see if it starts.... If it does, have the carb rebuilt.
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on the top of the carb there is a small tube, and just poor the gas down that and it will fill the carb bowl with gas and it should work from there. also another way to see if there is gas in the carb is to push the accelerator pump and see if it squirts a small stream of gas down the intake and that would let you know that gas isn't the issue. Good luck

[Stocker]

Update: Got my tools out this morning, siphoned gas so I could prime the carb, and gave her a shot of starting fluid. Hit the key once and darned if it didn't fire up instantly and idle smoothly. Revs up just fine. Drove down to the lumber yard and picked up some boards... started up and drove home just like it should.

I have no clue. I've been driving this truck since 1977 and am well aware of its little quirks, and it's only actually stranded me twice -- once with a bad coil (since changed to HEI) and once when a battery suddenly failed.

At this point I'm guessing it may crap out again, and I have a couple leads I'm working on to find the right guy to rebuild the q-jet next time it fails. And I have no long trips planned....

[Crabass]

I have a number of vehicles that sit a lot more than move, and I've found that adding fuel stabilizer makes a world of difference for reducing fuel system problems. I don't think I should be recommending brands, that is something I believe should be chosen personally, but I will tell you that I use two products mixed. I'm convinced it makes a substantial difference and worth the cost and effort, but I'm not an expert and offer this as just my opinion.