So I am running a single Stromberg 97 on my stock model A engine. It is Running to rich at this point, it is a new Stromberg 97 with the original jets. I do have a fuelpump and fuel pump regulator that is set at 2psi. What size jets are you guy's running?
I would have thought a single 97 with stock .045 jets would be fine on your 4 banger, you may want to check your float level, I have purchased several new 97 over the years and had a couple where the float level was set to high straight out of the box causing overfueling.
I have the same setup in a Model A. I tried to go to leaner jets (.043) and it was too lean. Now use stock .045 and #65 power valve. If your plugs are rich you might try one step down .044. Also fuel level as mentioned. John
I had a new Genuine 97 that came with the seats and threads slightly misaligned in idle screw holes. Screwing in by hand felt like the screws had seated when they were actually open..
The 97's do not vent the fuel bowl to the throat. A restrictive air filter will make them run rich. The original airfilters were really just screens.
I have multible bangers with stromberg carbs... they all run too rich, but I seem to chase from the carb to the ignition and back and forth... all mine seem to run better with the air cleaner on...
I'm running a pair of Stromberg 97's from England on an Eddie Meyer early intake manifold. Engine is an early 59A flathead with a 276 displacement. The England Strombergs come with .045 jets from the factory. I found they were way to rich. Dropped the jets down to .043. Still too rich. Dropped jets down to .041. Better but still rich. Dropped down again to .039 jets. This is where we ended up with the jetting and the engine runs nicely with the .039 jets.
Question - how did you determine it was too rich? Did you have O2 sensors in the exhaust? If it did it by reading plugs, what was your process for reading them?
Actually it is quite simple. I'm running a 1929 Ford coupe highboy open hood no fenders and you could always notice the slight small of gasoline and there was always a slight backfiring or a popping out of the exhaust. As the size of the jets decreased so did the gasoline smell and the very slight backfiring became less frequent. With the.039 jets the backfiring stopped entirely no noticeable gasoline smell. The engine runs smoothly and probably the best it has ever ran. The timing is right where it should be and I always run the no alcohol gasoline with a bit of Marvel Mystery Oil mixed in to keep everything running smoothly.
I got to ask, Genuine Stromberg or knock off? I have found the speedway ones are very hit or miss. Is is fouling plugs, or just stinky? Have you tried driving it yet and see if it clears out? Just saying, the way these fuel the jets don't have much if any bearing on idle mixture at all. Float level can throw things off, along with too much transfer slot open. Easy way to check transfer slot is to look down the throat of the carb when running, if the boosters are dripping fuel your baseplate butterflies are open too much allowing it to flow through mains and idle circuits.
I thought 97’s had multiple fuel transfer holes, not a transfer slot? I could be wrong though. cheers, Harv
I forgot about the 2 different holes, the 94 Holley has a slot. Never the less if the butterflies are too far open it will pull from mains. Hence why I said to look down the throat and see if the mains are dripping. This shows air getting pulled by the emulsion tubes and fuel getting discharged. It can also be a sign of float being too high also as it will drip when motor is off.
cool post.... what was happening on mine was the float was out of level... causing the top of the carb to push the float down... which seemed ok if you drove alot.... but how I figured out it was doing that, it was in storage andI forgot to do the shut off valve and all the gas filled up in the oil pan... that and I had a constant rich condition that I kept looking at the jets... with the float set to be able to shut the fuel off the gas in the bowl was too low....so I had to take the float out and bend the tab to where the float was level with the carb base as to not hit the top when it was on......so with that fixed (hoping so) I now can look at the jetting to tune it... also looking at the weber conversion... so far every one I've talked with says it's well worth doing...
they look kinda like a chick with bolt ons on her back...I could see where it might work.... but look weird...
so chasing gremlins..... i got it fixed...put the battery ground cable direct to the motor in stead of the frame... car has float a motor front and back then grounded the motor to the frame.... fixing the fuel leak to the motor pretty much fixed the oil leak, gas was dumping into the cylinder and down to the oil and thinning it out....see'n the 39 jet worked so good on my other B bangher... but no header.... I started with a 41....Damn she runs good now.... and changing the ground made my amp gauge shows 15 more amps... where as before it showed zero or 2... so my next test will be to unhook the accelerator pump rod,,,, and do a plug test
I ran a 44 jet on a Stromberg 97 with my Model A four-banger and 6:1 head. That was on the advice of Uncle Max. Worked great.
mine is running realy good, but haven't plug checked... just driving it ramps up quick and crisp... close enough for an afr meter to fine tune... my only concern now is the power valve...
I have two stock Stromberg 97s with .044 jets: - 268 CI 59A block - 4" Merc crank - 0.400 Offenhauser heads - Isky Max 1 cam - Dual Stromberg 97s It runs great but I've considered going larger by testing with an AF gauge and O2 senders. Good discussion with some experienced experts on the BARN https://www.fordbarn.com/forum/showthread.php?t=56340&highlight=main*jets
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