Stromberg S-jet

C

Charles Brock

Senior Member
I have 4 new Stromberg 97 carbs with the S-jet Fuel Inlets and all 4 S-jets stick.
These are on two different 8ba motors with 2x2 intakes and electric fuel pumps.
After sitting for several weeks, the S-jets are stuck closed and cannot get fuel to Carb. Have to remove and blow out with air to get unstuck!!
What can be done to eliminate this problem?
Thanks
 
Charles,
I have run into this problem as well.. I removed them and used NOS needle/seats and have had zero issues since.. My 33 is my only car with a S-Jet.. It doesnt hang up but I run a heavy mixture of Lucas fuel additive oil in that car, and that may be why..
 
I had one stick on my Model A after about 10k miles. Car just would not start and hard to diagnose.I had to replace it. I have 2 more 97s on my roadster and they are fine at about 4k miles.
Would be interesting to see what others say.

John
 
Been running mine since the new 97's came out. One stuck open once and they replaced the plastic floats with brass ones and I never had a problem again. I only run non oxygenated gas, no alcohol.
 
Drove a couple hours, parked a couple hours on a really hot day. When I fired up to return home, I had a problem with my tri-power 97's running a little rough at high speed (secondaries open). It cleared itself up after about 20 minutes. Suspected one of the secondary carbs was not feeding, but no way to check, since it cleared up.

Sat a couple weeks and I pulled the carb tops off to re-jet. Since I had the tops off, I did the invert and blow check that the inlet valves were sealing. All fine. What was not fine is that both secondaries were also sealed with the carbs upright. The float drops so the valves should be open. Shot a blast of carb cleaner through the inlet valves, and normal operation returned.

Conclusion: Something is causing the ball in the valve to stick to the seat. I run regular gas with ethanol, so things should not gum up that easily. I also put 4 oz of MMO in the tank every time I fill up. I wonder if that combination of MMO and alcohol could be causing the problem.

Anybody else with the sticking S-Jet problem using MMO in their gas?
 
Now, stand by for your next issue.
Spray carb cleaner will attack the leather of the accelerator pumps and cause them to swell up like your big toe. After they sit for a while and dry out, they'll become lodged/stuck in the wells.
 
I have posted this quite a few times before and here it is again.
If you can find rebuild kits with neoprene tip needle valves, you will have no leak by when the engine is turned off. They will also hold 8 lb. of fuel pressure.

A little known fact, on a 276 ci or bigger engine, 3 Stromberg 97's will go dry at full throttle after 3 seconds with only the popular 2 lb of fuel pressure. 3 seconds at full throttle is actually a LONG time so most people do not notice it.
6 lb will keep everything going.
 
We recently overhauled a Stromberg 97 for a customer. The cost of parts kits are high, and if you don't have the special wrench, you will probably be out of luck, as our supplier says they are no longer available. These carbs, with the "emulsion tube" design have always been tricky to maintain. That probably why the "94" carbs superceded them in 1938.
 
Follow up on soft tip needle float valves mentioned in post #8.
They come in kit number 697 from Daytona Parts Co.
I bought 30 of those kits in the late 70's and they still work good.
They called it Neoprene back then. It is Viton now.
 
supereal said:
We recently overhauled a Stromberg 97 for a customer. The cost of parts kits are high, and if you don't have the special wrench, you will probably be out of luck, as our supplier says they are no longer available. These carbs, with the "emulsion tube" design have always been tricky to maintain. That probably why the "94" carbs superceded them in 1938.
Click to expand...
The struggle is real.
 
Gotta say while on the topic, there is nobody out there that rebuilds them where they look half as beautiful as Uncle Max.
 
Tim: I am not aware of brass needles for the inlet valves unless they are Vitron tiped. The body is brass but the all metal needles are steel.
The original Ford or the early reproduction inlet valves with all metal needle and seats work great if your looking for a replacement.
 
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I went through a couple of bad S jets on my tri-power flathead back in '09 with my new English 97s, but changed all 3 S-jets from Uncle Max and have had no problems for the last 20K miles. I always use high test pump gas, usually Marathon or BP.
 
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Terry said:
Tim: I am not aware of brass needles for the inlet valves unless they are Vitron tiped. The body is brass but the all metal needles are steel.
The original Ford or the early reproduction inlet valves with all metal needle and seats work great if your looking for a replacement.
Click to expand...

Terry

Thanks for the correction. Yes, I meant steel. Seat is brass, needle is steel.
 
Have never had a problem with the S-jet in the English Stromberg carbs but have never used ethanol fuel either. I do use "Flashlube" in the fuel tank which is like MMO as I don't think we have MMO in Australia. Come to think of it I never had a problem with the original Stromberg needle and seats either. The only faulty one I ever had was the neoprene soft tip needles. Regards, Kevin.
 
Tim Ayers said:
Haha. Max, you are playing coy and it’s understandable. You are still supplying S Jets with your rebuilds, so can one assume they are safe to use?
Click to expand...
The S-jets are just fine IF the car is driven regularly.
If the car is dormant for weeks or months, sometimes the S-jet can become susceptible to varnish, additives or other contaminants in the evaporated fuel. A lot depends on the particular recipe of your local gas!
One big stainless ball - closest to the tang on the float - bumps against the other smaller ball and meters the fuel, while spinning and throwing off small debris, as the fuel pump pulses. They will also withstand a bit higher fuel pressure, although 2 to 2-1/2 lb. is about right.
 
My experiences indicate the "S-Jet" is extremely sensitive to dirt/debris. Even a filtered system can cause problems if micron levels are insufficient. However, I have tested several of the new English Strombergs and "S_Jet" with 7 lbs. of fuel pressure and had NO FLOODING.

This is not a suggestion to run at high pressures.
 
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