I am happy. I did have an off idle stumble when jabing the throttle agressively. When looking through some old car magazines, I found that raising the float levels can solve the problem, so I did that. Guess what - problem solved! Maybe I'll keep that thing after all!
That reminds me of the time I rebuilt my quadrajet. When I started the car after installing the carb again, it kept flooding big time. Then I figured out I installed the float upside down! :rant: ou:
I raised it to the point where the gas was definately leaking (eeking?) out at idle. Before the adjustment, my fuel level was just to the point at the bottom of the threads of the bowl level window screw hole. This got me thinking. The people with the clear sight plugs MUST have their fuel levels higher. That is the only way that they would see their levels in the first place. I may raise it higher if need be. It worked. Try it if you have any lean / stumble issues.
I have a slight stumple,i also have the clear sight plugs,should i go about half way on the sight plug? Thanks
Yes, that is exactly whay I'd do. ALSO - make sure that your accelerator pump arm(s) have zero free play at idle. If there is play, unscrew that spring loaded screw on the pump arm(s) to take up the slack.
And to think that, years ago, I blew up my starter by advancing the timing to try to get rid of the stumble. LOL. I'm definitely going to remember this thread when I get around to rebuilding a carb again.
Andrew, I've been having the same problem with my carb. I think we're running the same carb on very similar engines. I know you cured the problem but I don't think you did the right thing. Running the levels too high makes the fuel dump out of the boosters and richens your idle. Thats why the problem went away. Your engine wants more fuel. If you pull a plug I bet you'll find they're black. I did a similar thing when I temporarily "cured" my problem by making the idle rich with the idle jets. It worked better but the idle was too rich. It ran ok that way but the plugs were black. Over time you can foul the plugs. What I ended up doing was drilling out my accelerator pump nozzels. I drilled mine because my supplier was out and I was impatient. I went with .053 ,so far, in the primaries and .040 in the secondaries. Now I'm smokin the tires off the line instead of stalling. I think I will go bigger in the secondary nozzel because it was larger than the primary to start with. Evidently Buick 350's love fuel off idle. I also found I was lean on my main jets and went up two sizes primary and secondary. Now my plugs are where I like them. Holley says all this crap about their carbs are jetted properly right out of the box. It doesn't apply to my Buick. BTW you may find that your lean/rich cylinder condition is due to your idle jets. They should end up all the same when you're done. Mine idles at 800 and 17" with 1/2 turn in all four idle jets.
There is a lot of info there and I appreciate it. When you went way rich - how high had you adjusted the floats? I only raised the fuel (float) levels by a fraction. I will keep an eye, but my plugs always tended to be white - too white, really. I also took up the slack in the primary accellerator pump lever. The sec was fine. It is interesting what you have said about the nozzles. I was actually thinking about messing with the pump cams instead. It seems to be idling well, with about 15" at 650 RPM right now. I'll post back with any findings
The 50cc accelerator pump is a good swap too. However... I had to file down the bottom of the pump arm and make a small notch in the top of the aluminum B4B manifold for it to fit. With a spacer I'm sure it isn't an issue, but it is on a stock manifold. Also, I just took my clear site plug out yesterday. And it came out in pieces. I was told last year to not use them, but never got around to getting the metal plugs. I'm lucky I had my fuel bowl off at the time so I could clean out the plastic residue that was left all around the threads of the site hole.
I've read over and over and over in HOT ROD and Car Craft that a motor w/ a fairly big cam needs higher initial timing, as well as float levels that never go above top 1/3 mark on clear site plug, but never below 1/3 mark either. Dunno if this is a Chevy rule......but I read that rule repeated a lot.
That sounds damn good to me. I have a 455 w/ a big cam, and I'm lucky to see 12" at idle. Besides.....those Holley DP (as cool as they are) seem to be carbs that need constant attention. Especially in Chicago, where humidity levels are as stable as the Dow Jones.
Well it was OK for years, but now I'm having a recurring "sticky float" problem. My old Q jet is a little trashed, so I ordered a rebuilt from AutoZone. I am going to try that with only a secondary rod and hanger changeout. I very much hope that it works!
