Stromberg 97 carbs leaking

Displayman

Displayman

Senior Member
I just installed a pair of rebuilt Stromberg carbs on a Fenton manifold.
Ran new fuel lines and installed fuel pressure guage. Set guage at
2 1/2 lbs. Car is 1947 Merc. 59 AB, mechanical fuel pump.
Dump some gas into carbs, fired up, then died.
Finally enough fuel pumped trhu to carbs. Front carb has minor leak from bowl, carb closet firewall leaking from bowl. I lowered pressure to 2 lbs.
still leaks, but not as much. Any thoughts. I was told that these carbs have a leather diaphram that needs to soak for a while before they function properly?
This is all new to me.
Appreciate any input.

Thanks,
Bob - Hampshire, Illinois
 
The "leather" is on the piston of the accel. pump. There is no chance it has any involment in the leakage. I would need a better definition of where the leaks originate to offer any help. It could be anything from holes in the casting to plug gaskets to float/needle problems.
 
Also...if you have the little chrome gauge/adjuster combination device, be aware that your pressure has absolutely no relationship to what the gauge says or what you do with the adjuster. These things are evil. To add to the fun, many available fuel pumps have diaphragm springs from some later application with much more pressure than a proper flathead one. Stromberg fuel level can vary a good bit with changes in pressure...after engine dies, do you have gas dribbling into carb throat?
 
Yes, after engine dies, there is gas dribbling into carb throat.
What does that tell me?

Bob
 
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These carbs were just recently overhauled by someone who does it for a living.
Is there a fuel pressure guage that somebody can recommend?

Thanks,
Bob
 
Gas level is likely too high, caused by either bad original setting OR inlet pressure high enough to blow gas past the inlet needle. This causes the dribbling and of course immerses the body/lid joint in gas.
Stromergs are ideally set by Fuel level, not float level, and set to that level with the actual pump. Needle closing is not as positive as it could be, and higher pressure fights the needle as it tries to seat.
 
A leaking carb is like asking how high is up. Where specifickly is it leaking.Rubber inlet needles are a problem and too high a gas pressure.PM me on who built these for you?? ken ct. It could be almost anything.
 
Displayman said:
These carbs were just recently overhauled by someone who does it for a living.
Is there a fuel pressure guage that somebody can recommend?

Thanks,
Bob
Click to expand...
Bob - I'm in a good mood... Send me your two offenders and I'll re-do them for the price of gaskets and "S" jets, plus 13 bucks for the mailman.
I promise no leaks, unless you want them for authenticity.
"Doing it for a living" is subject to speculation... :rolleyes:
The Malpassi filter/regulator - used on old Ferraris is adjustable from 1 to 4 lbs and looks right at home on flatheads.
 
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I've posted this before - but even my Stromberg 97 coffee cup leaks, really. I guess it's just the nature of the beast.

Lee
 
Uncle Max, I think it's great what you offer the person. What if the issue is in fuel pressure? At least they will have been touched by knowledgeable hands, (yours)...That's a complement..
Duane...
 
Nice of you to offer that max,his problems could be almost anything. "doing it for a living" dont mean a dammed thing there are some hackers out there.LOL with 3' of snow and ice out here in ct. uggg ken ct.
 
Max,
I turned the fuel pressure gauge to 1 psi.
Car runs great, but races, need to turn down idle.
The carbs are not leaking when running now,
and very little drips out after car is shut off?
I still might take you up on your generous offer.
Bob

Bob
 
If you turn down the idle on 1 carb you must turn the other one also,other wise you upset the sync on them.Disastrus situation if not done. OMO ken ct.
 
uncle max said:
Bob - I'm in a good mood... Send me your two offenders and I'll re-do them for the price of gaskets and "S" jets, plus 13 bucks for the mailman.
I promise no leaks, unless you want them for authenticity.
"Doing it for a living" is subject to speculation... :rolleyes:
The Malpassi filter/regulator - used on old Ferraris is adjustable from 1 to 4 lbs and looks right at home on flatheads.
Click to expand...

Where can you purchase the Malpassi filter/regulator? Thanks
 
Max did a GREAT JOB rebuilding chrome Strombergs for me a few years ago. I highly recommend his work. There were NO LEAKS on these carbs 3 yrs running.
The engine started great, idled perfectly, and ran like a top. I drove 70mph for 9 hrs during 4th of July weekend (Mpls to Des Moines and back) and it ran perfectly with no leaks.

Quality work, good communication, and fast turnaround. It doesn't get better than that... unless it's free!
 
Displayman,
If you feel like it remove the air horns and eye ball the float
level...the floats should be slightly less than level when the needle is
seated in the brass inlet fitting. The right side of the float should be
lower by about .030- .040. Of course a fuel level gage is the proper
method but this will get you close.
Double check also the small tab on the inlet side of
the float...the tab contacts the needle, be SURE there is no wear mark
where the needle contacts the tab. Surprisingly a small mark can cause
fits. Notice also the right angle bend at the top of this tab...it is there to
deflect fuel downward as it enters the bowl. It's good to have it there but
too often this bend can interfere with the inside of the bowl and occasion-
ally keep the float from properly seating the needle in the brass inlet.
Having said all this I'm guessing you shouldn't really need a
regulator with a mechanical pump.
In my humble opinion the small Holley fuel pressure regulator
is superior to others....just my opinion.
OR
Send 'em to Uncle Max in Utah.
Charlie ny
 
Charlie ny said:
Displayman,
If you feel like it remove the air horns and eye ball the float
level...the floats should be slightly less than level when the needle is
seated in the brass inlet fitting. The right side of the float should be
lower by about .030- .040. Of course a fuel level gage is the proper
method but this will get you close.
Double check also the small tab on the inlet side of
the float...the tab contacts the needle, be SURE there is no wear mark
where the needle contacts the tab. Surprisingly a small mark can cause
fits. Notice also the right angle bend at the top of this tab...it is there to
deflect fuel downward as it enters the bowl. It's good to have it there but
too often this bend can interfere with the inside of the bowl and occasion-
ally keep the float from properly seating the needle in the brass inlet.
Having said all this I'm guessing you shouldn't really need a
regulator with a mechanical pump.
In my humble opinion the small Holley fuel pressure regulator
is superior to others....just my opinion.
OR
Send 'em to Uncle Max in Utah.
Charlie ny
Click to expand...
Good point Charlie,i usually cut it a little shorter so it dosn't hit the housing. ken ct.:)
 
why don't someone make a needle and seat to take teh 5-7psi like the regular carbs have and you wouldn't have the pressure problem with 97's and also 94's
 
I have run the new Strombergs, with the ball valve(S-Jet) inlet, at 7 lbs of fuel pressure and it worked fine on the dyno. Not recommended for road use where sloshing is much different. The major reason the Stromberg is so damn susceptible to leaks at the inlet is because the leverage at the float pivot is not designed for higher than a couple of pounds.
 
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