Steel Needle Stromberg Carburetor

[VictorBravo]

If anyone has a source for the all steel needle and accompanying needle seat for the Stromberg carburetor, please let me know. I want to upgrade an older rubber-tip needle to the steel one. If someone has a really good condition used set, or knows who sells the new ones reasonably, please contact me offline victorbravo (at} sbcglobal [ dot} net.

[Guest]

Re: Steel Needle Stromberg Carburetor

Fresno AirParts

559-237-4863

[Gary Snell]

Re: Steel Needle Stromberg Carburetor

You might also consider the delrin needle. It uses the same seat as the neoprene and tends to seat better than the steel. You will have to add a small counterweight to the float if you use the delrin. Last I knew Robert Weber in the Fresno area had the needles. You can find his number in TAP.

[SOPWITH2K]

Re: Steel Needle Stromberg Carburetor

I just did my carburetor and got the Needle & Seat (steel) from Aircraft Spruce. Not cheap but solved all the problems. Had delrin and could not get it to seat properly.

Paul Girard
BC12-D N95318

[Frank DeBartolo]

Re: Steel Needle Stromberg Carburetor

Ther is a place in Illinois that overhauls Stromberg Carbs. They have all the parts, floats, needles, seats etc. In my opinion, the steel needle is best. There are two other needles, one is affected by other fuels and tends to distort, swell and cause bad problems. This needle is rubber tipped and was designed for 80-87 gas--which we can't get any more. The other I think is the delrin needle but a small counter-weight has to be put on the float because the needle is so light in weight. The steel needle may leak a little at times when it sits, but I routinely shut the fuel valve off when finished flying--it never leaks with the fuel valve shut off. There is a way to keep the Stromberg from leaking but you either have to really know what you are doing to accomplish this, or send it in to the Illinois shop. According to the boys at the Illinois shop, there is a tailwheel mod to the Stromberg Carbureator that keeps it from leaking. The Carb is typically set up to keep from leaking in level flight position but with the tail down it can leak. The boys at the Illinois shop expained this to me. I never did send in the carb because my IA overhauled my carb, but we never did the tailwheel mod--I just shut down the fuel valve when the airplane is not in use. Been doing this for over 5 years now and works great. I am happy with the stromberg and know that Stromberg carbs can leak when sitting. Answer to that is shut off the fuel valve. I believe that the Strombergs are darn good and very reliable. Only downside IMHO is that there is no mixture control.

Frank D
N43684

[VictorBravo]

Re: Steel Needle Stromberg Carburetor

Thanks for the info guys! I have always shut the fuel after flying... ever since my first T-craft fuel tank was empty after a couple of weeks sitting! I ran around the airport with a loaded pistol looking for the bastard who stole my (!($#$% gas!

My Stromberg has a mixture control. It works just great - if you think that leaning the engine out only 75 RPM at 8500 feet is great I am told by Stromberg expert and Forum member L-2 Gary that above 10,000 feet it starts to do something worthwhile.

I'll see if I can find me a steel needle. I had flown one XC flight using 20 gallons of car gas that the station owner SWORE had no ethanol in it. I wish HE had been in the airplane with me when the engine balked on takeoff... for the third or fourth time in recent memory !

[mike lutz]

Re: Steel Needle Stromberg Carburetor

in the past i have used the steel needle and found that if you lap the needle into the seat with pearl drops tooth paste it will seat and not drip.ALTHOUGH,I would still make it a practice to shut the fuel off when done flying for the week.

[Frank DeBartolo]

Re: Steel Needle Stromberg Carburetor

Tribe,

It has been 5 years since I talked to the shop in Illinois and don't know if they are still in business but I found the invoice for parts I bought from them 5 years ago. The name of the business is Aircraft Systems, Inc. Their address is as follows:

Aircraft Systems, Inc.
Greater Rockford Airport
5187 Falcon Road
Rockford, Illinois 61109

Their phone number is 815-399-0225

Frank D
N43684

[flyguy]

Re: Steel Needle Stromberg Carburetor

I can confirm that the steel needle causes drips on occasion. Ditto on having to turn the fuel valve off.

I aways assumed that it was the intolerance of metal to metal for any small material getting between the hard surfaces. Think the angle thing is more likely though, now that it has been brought up.

Had a small block Chevy that would do that and idle rough with black smoke. Solution was to tap the carb with a wrench. Worked every time, LOL. NO IDEA where or how I learned that.

The guys at Fresno Air Parts are really good to deal with (notwithstanding the tone of their TAP advertisement.)
Darryl

[Richard Boyer]

Re: Steel Needle Stromberg Carburetor

When I first started flying my Tcraft I only used 100LL. After some time I switched over to car gas. My carb started leaking after shutdown. That is when I started using the fuel shutoff to kill the engine. As a side benefit, it means less of that crap gas in my carb!

I found that the blue die in 100LL actually acts as a kind of leakstop. Regular car gas softens and removes the blue die......

[NY86]

Re: Steel Needle Stromberg Carburetor

there is a tailwheel mod to the Stromberg Carbureator that keeps it from leaking. The Carb is typically set up to keep from leaking in level flight position but with the tail down it can leak.

This is independent of leakage due to the needle valve. The original Stromberg design placed the air bleed jet just below the parting surface of the carb body. some taildraggers sat at a high enough angle that the air bleed was at or below the level of fuel in the bowl, and the fuel would dribble out the bleed jet when the plane was sitting. The fix is to relocate the jet into the carb body cover so it was always higher than the fuel in the bowl.

The original needle was steel. Since it was prone to leakage, the neoprene needle was introduced. This worked fine until about 20 years ago when gasoline started having more and more additives, many of which attack neoprene. (Some say the real problem was sub-standard, off brand needles.) Enter the Delrin needle. It's immune to just about anything but it's not as pliable as neoprene, so slightly more prone to leakage. As mentioned, it is so much lighter than the steel needles a weight is required to give the correct pressure on the valve as well as to counterbalance the float.

The steel needle employs a sharp edged seat. Lapping compromises the sharp edge, making it more prone to leakage from contaminates, but sometimes it's the only way.

My Stromberg has a mixture control. It works just great - if you think that leaning the engine out only 75 RPM at 8500 feet is great I am told by Stromberg expert and Forum member L-2 Gary that above 10,000 feet it starts to do something worthwhile.

You're confusing the cause with the effect. Think about it. Why do you get such a great RPM increase when leaning a Marvel carb? Answer: because the Marvel mixture is way to rich. Why no big increase with the Stromberg? Answer: because it's already close enough.


Whacking the Chevy carb with a hammer freed the stuck float...

[flybikefarm]

Re: Steel Needle Stromberg Carburetor

Aircraft Systems is still there. They still do great work. George

[flyguy]

Re: Steel Needle Stromberg Carburetor

"Whacking the Chevy carb with a hammer...." REALLY, I'm more sophisticated than that; it was the end of a WRENCH. Chuckle.

I agree that the Stromberg must be pretty lean in the mid range as I get about the same results as Bill. I think it is working ok though as I can adjust the mixture even with it at 14-1500 RPM.

While we're on the subject. Central Calif has a lot of farming. It doesn't rain here in the summer. They plow a lot around here. We are talking dust. I note that the mixture adjust has VERY SMALL holes in the rotating plate. Carb heat gets checked on the ground which means sucking in air without it coming through the filter (Right?). Any comments on that?
Darryl

[VictorBravo]

Re: Steel Needle Stromberg Carburetor

Thank you NY86 for a clear explanation. I appreciate it.

Is there any reason that hand-lapping the original all-steel needle to the seat using jeweler's rouge or something like that would not cure the problem? I even heard one recommendation to whack the needle into the seat with one good hammer blow to "seat" it. That seems awfully crude even by my standards!

A well known local engine expert verified that there was indeed a very large batch of rubber tipped needles manufactured and sold with the wrong rubber compound, resulting in significant problems.

[Robert Lees]

Re: Steel Needle Stromberg Carburetor

Had delrin and could not get it to seat properly.

Apparently mayonnaise is the lapping compound required for the Delrin needle.

Do a Google for stromberg.pdf ...very informative. I have a copy, but it won't load to this forum due to its size (600kb) , but it's readily downloadable from the net.

I've just had an A-65 carb overhauled with a delrin needle..it works fine.

Mayonnaise! They said it is slightly abrasive for scratch removal, and that the oil in it helps preserve the plastic. I put some on the needle and proceeded with the lapping again--(by this time well over an hour has gone by).

The needle had a dirty ring around it at the seat contact when I started. After working it with mayonnaise a few times, my glass inspection found the fuzziness almost completely gone, and the needle squeaking in the
brass seat, indicating that my seat was getting pretty good. I think the key to all this is to GET RID OF THE FUZZINESS, which may appear to be a good seat, but allows leakage.

...

Isn't it amazing that something so simple and straightforward can be such a pain to get working properly?!