I need some help from the 97 experts here on the board. I'm putting dual carbs on the 276 flatty in the T roadster (the one in my avitar). I've rebuilt two 97's for the project. Bolted them on the flatty one at a time for tuning before taking the plunge to two carbs & intake (I learned that lesson the hard way awhile back). The first carb runs great, but the second has some issues. It has large amounts of gas coming out the emulsion tubes, even at idle. So much the engine floods out and dies. I'm running a pressure reg and using the ball style (gross jet) inlet from Clive at stromberg. I've pulled the emulsion tubes a couple times to check for blockage, but found none. Jets are the same in both carbs. I'm wondering if something in this carb has been drilled out for alcohol? The air bleed holes look normal size, but it's hard to tell. Does anyone know the size of these holes (maybe using a # orfice drill bit?) Any ideas or help would be appreciated.
run it with the top off and check the fuel level in the float bowl...think you have a bum float valve
Drilling wouldn't matter, as that circuit should be inactive at idle anyway. Fuel level wildly wrong, excess pressure, bad inlet valve. When you find the prob you can set fuel level with lid off, but I wouldn't try running it with the lid off right now!! Bad or fouled float inlet valve would certainly seem the likeliest. You could swappit with the one from other carb as an easy test.
Thanks for the tip - Forget to mention that I have checked fuel level & float with the top off - fuel at 1/2". Float appears to be good, no bubbles, no residual gas in the float.
Already used old style steel needle & seat, now the new style gross jet with same results. Holley fuel pressure regulator down to 2 1/2 pounds. I set the float level (fuel level) on the bench with the top off feeding from a small project gas can. I've been messing with this carb for awhile and it's driving me nuts. Both carbs should be identical and I'm just swapping the carbs on the same engine. One is great, this one sucks......
Swap in valve, float, axle from good carb and see what happens. If this cures it, swap back one piece at a time til culprit is identified. I would try old steel needle and inlet fitting, "Rebuilt" by tapping needle into its seat gently with a tiny hammer, rotating and repeating. I have NO experience with Grose jet...new ones are probably good because from good sources. There are several generations of the old ones, with reputations varying from good to three-alarm fire.
I'll try the swap plan tonight when I get home. The grose jets are new stromberg pieces from Clive. Been dealing with this issue for quite some time and a local stromberg builder (Baxter's) recommended I give the new inlets a try. I've still got several NOS steel needle & seat assembly's to try also. Some in early ford boxes and others in wood tubes.
I'm no carb expert but what I do know is that on my 2-94s on a 255 cube flattie, I do not run over 1 1/2 lbs of fuel pressure. Although this may not your real problem, this may help things a bit.
Is there fuel leaking through the accelerator pump hole in the air horn, usually due to sticky float. Is gas leaking through the power due to bad gasket, is check valve stuck. Is the accelerator rod the same on both 97s and set on S or W.. ?????????? Duane.
Pull the tubes and cleanem again, maybe?? Maybe air holes in casting and tubes blocked allowing syphon? Grasping at straws here?? And...reverse the last experiment...float stuff from bad carb to good one. I think that stuff will be exonerated, now, allowing us to plumb deeper problems.
I think the question is, how is the fuel getting to the emulsion tubs. The tip of the tubes is higher then the fuel level in the bowl, how can it syphon????????? Duane..
Er, you did replace the main jets and tighten them down didn't you? If not there is where your fuel is coming from. When you removed the immulsion tubes did you reseat them properly? Check this area before playing parts changer.
Tighten down the jets means, to just bump the jet against the emulsion tube enough to seal..If you tighten to hard you will collapse the small holes that are close to the tip of the tube..There is either two or four holes. Also both tubes should have the same holes, both with two or both with four.. Duane.
I've had the jets & emulsion tubes out more times than I can count. The holes in the tubes are round (not collapsed) and both tubes are the four hole variety. How can I verify the jets are seated on the emulsion tubes? After a couple rounds last night, the carb is at the point the engine will idle, but there is still gas coming out the emulsion tubes at idle. Obviously not right. I was frustrated to the point of pulling out a couple 97 cores from my stash to find another decent body. How can something fairly simple with few parts be so complicated?? The parts/cleanliness/assembly between the "bad" and "good" 97 appear identical - that's what's so frustrating about it.
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