Steel Needle Stromberg Carburetor

[Richard Boyer]

Re: Steel Needle Stromberg Carburetor

I have never experienced anything like this. I guess it is because I avoid places where water can become a solid...... I can go from no throttle to full and not experience any lag or splutter in power (this is with a stromberg.....)

[NY86]

Re: Steel Needle Stromberg Carburetor

OK, one more crack than I give up. If a carb needs to be leaned then leaning will result in an increase in RPM. In the full rich position the Stormberg does not run rough, hence it is not way off on either the rich or lean side. If moving the mixture control does not result in an RPM increase, no leaning is necessary. A Marvel carb can not perform any better. If leaning the Stromberg does result in an RPM increase (and it will once you get above about 5000') then you still achieve the correct mixture and again the Marvel can not perform any better. Ergo, there is no place where the Marvel carb will give you any better fuel consumption numbers over the Stromberg. On the other hand, if you didn't lean the Marvel, the Stromberg would definitely give you better fuel consumption numbers, but then the Marvel would run like carp if you didn't lean it.

As far as cylinders running cooler goes, you can not make cylinders run hot by running too lean at power levels below 75%. The only thing you can do is make them run cooler by running too rich. But, there goes your fuel savings...

Also, it is not nor ever was a "Precision" carb. It is a Marvel Schebler carb. The name "Precision" has no bearing on the precision or lack there of of the carb. At one time the rights belonged to Precision Engines, but no longer. At one time both Marvel Schebler/Tillotson and Stromberg were Bendix products.

TMSAISTI. I can buy fuel for years with the money I didn't spend on a Marvel carb...

[flyken]

Re: Steel Needle Stromberg Carburetor

The Precision Carb - that was the name on the box it came in - I got was off a wreck (fuel management issues). It had less than 20 hours on it and I didn't pay full price - in fact the guy threw in a good Hanlon Wilson muffler too (slightly dented from the wreck). I was doing quite a bit of winter flying at the time. Repeatly on final thru an inversion, the ol' Stromberg was slow to adjust to air temp changes (going from 0 c to -20c or more) and to power adjustments when already at low power settings(on final) which meant getting stuck on wet/deep snow. And yes over the years I had overhauled it and gone thru the period of steel needle, then nylon needle then nylon tip needle and back to whatever needle. I knew the Precision/Marvel worked well in the cold climate (cause the guy that sold it to me said it would he used to have a stromberg too) so it was time for a change. Now because the Prec/Marv carb has an infinite mixture control you can more accurately set and control mixture. As for saving fuel, by adjusting both throtte and mixture you can lean at your desired rpm and go from there. The prec/Marv carb actually mixes the fuel and air more efficiently/effectively so you save fuel there too. Now one last thing about About the Stromberg mixture control and this is why so many have been removed/tied off is dirt does get in there and constricts those apertures a bit. What will happen - if you don't have a cht gauge - is lets say normally in cruise your oil is 100f higher than outside temp so on a seventy degree day your oil temp should be 170f. You notice that your oil reads 180 but it is only 70f outside. Your ame or friends say don't worry about it so you keep flying around. 30 hours or so later you are definitely using more oil than usual, you pull your plugs and they are brown - you pull a jug and the rings and pistons are cooked because you have slowly been cooking your cylinders they were prob about 50f higher than normal but the plane developed power ok and with no cyl head temp gauge you didn't know. So now you get to do a top overhaul. The oldtimers at continental could have told you this 25 years ago but I doubt any are around now.

[flyken]

Re: Steel Needle Stromberg Carburetor

As for the details of exactly how the Prec carb works its been a long day, my mind is numb and my fingers are already worn out from the previous input so maybe someone more eloquent than me can do that. (And I know I'd leave something out and get called on it - not an AME just a dumbbutt pilot.)

[larrysmith1016]

Re: Steel Needle Stromberg Carburetor

Go steel, go steel! I have delrin and steel on two diff engines and steel is better.

If you install it make sure your float level is correct, then lap the needle in, and sometimes you have to whack it gingerly with a rubber hammer. I lap first, then whack. Never get a leak with steel, but the delrin leaks sometimes.

[flyguy]

Re: Steel Needle Stromberg Carburetor

All the young guys working on their first cars would have a problem and immediately go for the carb. Never fixed the problem.
We always said "You think you have a carb problem, fix the ignition." Talking about the days of points and dwell meters and such.
My recent experience with the 30's era ignitions we have on our aircraft has left me a bit amazed that the engines actually run at all.

On mixture controls, what I have found is that it works fine to lean the mixture, but I couldn't get quite the results that I expected at 10,000 feet. I would not doubt that it is a problem with the operator in this case. Will play with it more later.

One last (sure) comment on the dirt in the AIR bleed holes. It is pretty dirty here, so after some time I will check it out and see if I have picked up any in the mixture plates. It is so tight in there that whatever goes thru might just fly thru the big hole and leave nothing behind.

Darryl

[flyken]

Re: Steel Needle Stromberg Carburetor

Believe what you want. There is a reason why continental went to the Precision carb - and a reason why this carb costs more to buy than the stromberg. I believe I have shown several reasons why the Precision is better. I flown both and know which is better. I flew the Stromberg for years and learned its short comings - as have others. The precision does a better job. You can buy expensive tires for your car too - and believe it or not they will give you better mileage, braking and performance for your car than the cheap tires. Some people prefer to make decisions with their wallet. Cheap doesn't mean better it just means short term less expensive. All it takes is a slight change in mixture to raise temps and cook cylinders. I'd recommend a CHT and EGT with any carb but again to each his own.

[flyguy]

Re: Steel Needle Stromberg Carburetor

Hope that last comment wasn't meant for me as I don't know doodley about "precision" carbs and really don't care unless I start flying C150's again. They worked fine for me back when I was flying spam cans.

But saying that a stromberg will burn up your engine because it isn't fancy enough is a little over the edge IMHO.

I only disagree with people when they make it clear, by what they say about machinery, that they do not understand the functioning of that particular device.

The Marvel carb is obviously a fine, reliable carb as witness many years of trouble free operation in the hands of ham-fisted students in the 150 series Cessnas. But the Stromberg is also a good carb even if somewhat less sophisticated, and I believe, like the much-maligned automotive Quadrajet that it actually has several features in the design that are a bit more subtle than most people appreciate.

I have found that, as per NY86, that my Stromberg seems to run on the rich side at full power down low and leans out as it goes up, witness the small change in RPM when peaked out at altitude. Suggest to me that there may be some compensation circuits in there somewhere.
Finally, yep, the Stromberg will choke down for a second if I happen to jam the throttle in like a 5 hour student, but it is about 46 down on my list of problems with airplanes as I try to avoid situations where that kind of reaction is required.
DC

DC

[Ragwing nut]

Re: Steel Needle Stromberg Carburetor

Precision OWNED Marvel for many years and if you ever got a new carb Precision is cast into the bowl, not Marvel.

[NY86]

Re: Steel Needle Stromberg Carburetor

Precision OWNED Marvel for many years and if you ever got a new carb Precision is cast into the bowl, not Marvel.

The implication was that it was called "Precision" because it was precise. My comment was that it was a Marvel Schebler before Precision stamped their name on it. Now it is a Tempest. If they follow true to form there will be no parts available, only factory rebuilds.

[flyken]

Re: Steel Needle Stromberg Carburetor

Well again a prob with the Stromberg over the years has been the mixture control. Just like it is hard to seat the rings on an 0290 lycoming and just like the middle cylinders like to cook on the 0435 lycoming and IO360 continental. Now I can get responses saying the 0290, 0435 and IO360 are the best engines ever and I don't know what I am talking about. I would have to disagree with those responses. If you are happy with your Stromberg by all means enjoy it but it does have its shortcomings. I flew the cont c85 with stromberg for years. When the engine got tired I put the 0200 crank in it and noticed a big improvement - wish I'd done it sooner. When I put vgs on I noticed way better control in crosswinds - wish I'd done it sooner. When I put the Maule solid tailwheel on (the lang was tired) I noticed an improvement on soft ground. - wish I'd done it sooner. Put in a skylite and got way better vis and more headroom - wish I'd done it sooner. When I got a deal on a precision carb I put it on and again noticed an improvement in cold weather flying, cylinder temp control and mileage - wish I'd done it sooner. So now I am telling those Tcraft owners who might be interested what I have found works for me and my machine - wish I'd done it sooner!

[NY86]

Re: Steel Needle Stromberg Carburetor

(OK, sometimes I just can't help myself.)

...When I put the Maule solid tailwheel on (the lang was tired) I noticed an improvement on soft ground. - wish I'd done it sooner.

If you'd fixed the Lang you would have been even happier!

Seems spending money makes you happy. Try a Scott 3200, it's about 10 times "better" than the Maul. You'll love it!

Well again a prob with the Stromberg over the years has been the mixture control.

Explain this, please.

The problem I see is with the pilot. Pull the mixture in flight instead of the carb heat. Problem with the mixture?

I had someone come in and tell me his CFI had told him to get the mixture repaired because it didn't shut the engine down. I explained how it worked and showed him how to kill the engine with the mixture control. Never did hear back from the CFI...

I can lean as much or as little as I choose. I fly out of a very short strip with trees on both ends. I have no issues firewalling the throttle for a go-around. I fly in the winter and have no issues with starting or running. I seldom even use the primer. The Stromberg altitude compensation is good enough that you can climb past 10,000' with out leaning at all if you cared to. Try that with a Marvel. My fuel burn is pretty much by the book. My spark plugs and cylinders are doing just fine. I've flown plenty of planes with Marvel carbs. I don't find them any better or worse than the Stromberg, just different. If your Stromberg can't do that, there's something wrong with it or with your procedures. If it can't be fixed, there's something wrong with your mechanic. Or you can duck the whole issue by getting a Marvel. Any idiot with an A&P ticket should be able to fix a Marvel (if you can get parts...)

Oh, and no AD's on the Stromberg...

All your "facts" are antecdotal. Bring data, like from a flow bench if you want to continue the discussion.

[dmcneil]

Re: Steel Needle Stromberg Carburetor

Hey All,

Geez, I hate to do this but I agree completely with John.

The Stromberg and the Marvel-Schebler are absolutely the same in terms of delivering atomized fuel to the engine. Both are stone age technology. Both work well when in proper repair. The Stromberg gives lots of people trouble because it's operation is so different than what modern A&P types are accustomed to dealing with. Pilots too, sometimes don't understand how the operation differs from more "conventional" carbs like the Marvel-Schebler. The Stromberg's altitude compensating abilities really throw a lot of folks.

There is a well known Luscombe guy who is an engineer by trade, Jack Norris. He was the technical director for the Voyager non-stop around the world flight. Jack understands efficient flight operation. For years he has been causing other Luscombe flyers to sit back and do some head scratching... and that's a good thing. Jack routinely covers amazing distances non-stop in his stock C-85 powered Luscombe. With a 30 gallon fuel supply, he regularly goes 700-800 miles non-stop. That is efficient flying. The carburetor on his Luscombe? A bone stock Stromberg NA-S3A1 which he always leans at cruise.

Dan

[flyguy]

Re: Steel Needle Stromberg Carburetor

Yep, works fine, last a long time, doesn't cost much. My kind of stuff, Chuckle.
Yo, John, My mixture control works pretty good I think, nice smooth plates, will kick in at about 1500 RPM and higher, but I don't know any tricks to get it to actually kill the engine, (higher RPM maybe?) Could you let us know more about that please.
Thanks,
Darryl

[flyken]

Re: Steel Needle Stromberg Carburetor

The reason why the maule tailwheel works better than the Scott is that as the scott tailwheel is higher, it lifts the tail up, reduces your angle of attack and makes your takeoff roll longer. Of course I am using carb heat on final. I believe I have explained the issue with the stromberg carburator and its limitations are known and have been known for years. As for spending money on the plane, yep, and I did it so I get to the places I want to get to more safely and more often - and it cost less than buying a supercub which I can't afford. I prefer the flight characteristics of the tcraft anyway. It feels the wind and lift better than most any plane I've flown and being lighter is easier to handle on the ground. As parts wear out on my plane I try to replace with the part that will do the job best that way I've got a little better plane and that makes me a little better pilot. You should do what is right for you I will do what I believe is right for me.