Got it back on the road and the hesitation is gone! But I made a quick cell phone video, you can hear a rattle that I don't hear when driving (my hearing is very bad). Think it might be detonation? I think the E brake handle rattles too, hope that's all it is..
Maybe. I ran wires though them but never saw any evidence of blockage. Could have come out with spraying/soaking. The two plugs under the mains had some white crud around the gaskets but other than that everything looked OK. Anyway, again appreciate the help and photos.
Suspect Moriarity was right. Suspect too that the OP on this thread (https://www.jalopyjournal.com/forum...–low-to-mid-range-only.1247670/#post-14294389) had the same drama, but never got any feedback from him. Cheers, Harv
Didn't find my answer so I wanted to drag this old thread back up to see if anyone has info for me. I have a hesitation off idle only. After that issue from around 1100 when it happens to when it clears up at around 1400, it runs great. Carb is set to around 950rpms at idle, pulling 16" of vacuum. I have 3 new 97 carbs from Uncle Max at 97 express with around 800 miles on them now. They are all 3 on straight pull linkage not progressive. Main jets are 42 and power valves are 67 in all 3. Engine is very healthy at 203 hp so I do need the fuel. I feel like it's either a lean off idle or rich off idle stumble. So far, I've moved the side linkage from summer to winter to just center winter, and no change. I've run the idle down to about 800 and no change. Note, it doesn't do it when the engine is cold for the first little bit, say under 130 degrees water temp. Seems to run worse after about 150 degree water temp and up. Thanks for the help!
Just pulled the plugs and they all look black except for the electrodes both the negative and center are clean. However the ground side should be clean all the way to almost the threads and it is not. I just purchased 1 heat range hotter plug. Going with the NGK BPR4ES. It shows the Autolite 405 plugs I'm running are a heat range 5 in the NGK, so one step down for a hotter plug. Hope to burn off the carbon and soot to get cleaner plugs. Maybe my hesitation is plug related?
What engine are you working on? 450 CFM is a lot of carb for a 200 HP mill. I ***ume it is a flathead. You are from SW Washington as am I. I had David Chun (RIP) tune my blown flathead. He told me before he would work on it, I needed to put a proper fuel regulator on it ("not the dial type" he said) at 2.5 psi and put progressive linkage on the three 97's or he wouldn't touch it. I did as he said, and the resulting tune made it run like a ****d ape. It still wears his tune to this day. He is missed. I am not saying this will fix your problem but it fixed mine. See ya on the street.
I actually stopped and talked to Corey about this off idle situation, his dad was amazing with carbs, he did many for me over the years. Over the last couple days I've been messing with different throttle plate positions, idle settings, and plugs. I am trying to find some consistency in the issue by replicating it or making it worse or better. It's not a fuel pressure or delivery issue; I've checked those many times over now. I don't think it's too much carb for this setup as they have been turned down a bit, in fact the car runs amazing minus this off idle issue. Progressive VS Straight pull is not a fix all option, some cars run great with or without. I was recommended to run straight pull by my engine builder, I had to rely on his expertise. However, I do plan to go down that road if I find that to be the problem. Signs just don't point to that being the issue. Personally, I think it's a crossfire or misfire issue right now, based on my findings. I tried a set of new plugs yesterday that made the issue worse across the board. In fact, it extended the hesitation from 1400 rpms to just about 2k. Plugs come in a million different flavors as we know and again a 1 size fits all don't work. I just need to find the winning combination, then move onto the next issue if in fact there is more. I will get it, I don't give up but I appreciate any info for sure!
Can you give the part number you used? Also, I would like to know proper vs. improper fuel pressure regulators. Trying to learn more.
I used the Holley 12-804, have one on my 442 as well. They can take in a max of 4 psi and dial it down to 1. I would think anyone would be hard pressed to find a reputable mechanic that recommends a dial type regulator. I put them in the same category as those gl*** fuel filters. Folks can use whatever they like, just make sure your insurance is paid up and have a fire extinguisher where you can get to it in an emergency.
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