STROMBERG UPDATE

(Zenith) Stromberg Carburetor – Model “CD”, “CDSE” General Exploded View The general design and parts shown will vary to individual units covered on this instruction sheet. N-1429 Disassembly Use the exploded view as a guide. Always disassemble carburetors individually as parts should not.
Haynes Owners Workshop Manual: Zenith Stromberg CD Carburetors: Don Peers. 5.0 out of 5 stars 2. 8 offers from $139.99. ZE21K, 15577C - Carburetor Repair Kit for Zenith 175CD 4.4 out of 5 stars 23. Customers who bought this item also bought.

Fuel “DRIP” – “CREEP” – “SEEP” / Normal-or-Abnormal?

Title: Stromberg 175 CD-2S Overhaul Author: Rob Created Date: 3/18/2015 7:49:19 PM Keywords. Hello, I'm new to this forum, and I'm working on a 1978 MGB that I purchased for my wife for our anniversary. It has a single Zenith Stromberg 175 CD on it and it needs a rebuild. I came across a 175 CD-2 and I was wondering what the difference is and if the CD-2 is i.

The Stromberg NA-S3 carburetor has been in use since the middle 1930’s and is a very simple and smooth running unit. Originally, it was designed to go on Fred Weick’s Ercoupe which sat on tricycle gear and on a level plane…
Then, the tail-draggers came along and used the little Continental and Lycoming engines with the same Stromberg. When the “tail-draggers” are parked, they sit at an angle of 12 to 15 degrees from level, even higher if the plane has “tundra” tires. During overhaul, the Stromberg Factory Service Manual requires the “float level” to be set “wet” to 13/32” below the parting surface of the lower casting. The float level is set with the carburetor in a level-horizontal position on the flow bench.

“FUEL DRIP – ABNORMAL”

There are several abnormal conditions that caused a FUEL DRIP to occur when the plane sits on the ramp not running…

Float level too high
Worn out needle & seat
Loose brass float bowl seat
Old, age hardened neoprene needle
Crack in lower casting
Loose main discharge nozzle
Float bowl vent mod (Stromberg Svc letter #73) raising float bowl vent position not done
Over-torque of the 6 screws holding the upper & lower castings together (causes warping of mating surfaces)
Leaking primer
Leaking fuel shut-off valve

Any of the above conditions are abnormal and unsafe requiring immediate carburetor attention

“FUEL CREEP – ABNORMAL”

When a Stromberg is overhauled, the float level is set to 13/32” wet on a flow bench. The needle and seat must be lapped to provide a leak-proof mating surface between them. When the float level is set, the technician must monitor the position of the fuel level for approximately 20 to 30 minutes to see if the fuel level slowly rises.
If this condition occurs, the needle & seat are not “fully seated” and they must have additional lapping performed to get a tighter seal where the needle & seat join together. Many times, during an overhaul, the technician does not take the time to observe this condition and rushes on to get the job done. This is a “VERY IMPORTANT STEP” in doing a proper overhaul and is often overlooked…

Stromberg 175 Cd 2 Manual

“FUEL SEEP – NORMAL”
(only in tail-draggers)

Stromberg 175 Cd 2 Manual Pdf

The fuel level, which was originally set in a “level” position on the flow bench, now sits at a 12 to 15 degree angle from level with the tailwheel on the ground. The fuel in the carb’s bowl now sits un-level and rests on the rear parting surface of the upper and lower castings. The gasket between the castings now gets wet and starts wicking up fuel from the float bowl. The fuel eventually seeps thru the gasket and ends up with a very slight leak at the outer edge of the gasket. This leak becomes evident by a small line of blue fuel dye at the rear and sides of the float bowl mating surfaces. Annoying, but not dangerous.
The pictures show the fuel level in the bowl and at a 12 degree incline. Note the fuel level at the 12 degree position…
People ask “why does this happen on a Stromberg and not on a Marvel-Schebler carb. The Marvel’s float bowl holds a higher volume of fuel than a Stromberg and the float level is lower than a Stromberg’s. When a Marvel-Schebler is used on a tail-dragger, the fuel level in the bowl obviously does not touch the gasket thus eliminating the “fuel seep” condition.
All in all, The Stromberg is an excellent little carburetor when serviced and overhauled properly. The key word here is “OVERHAULED PROPERLY”.
If you have any questions, call me at 708-267-7111 or email me at This email address is being protected from spambots. You need JavaScript enabled to view it.
Bob Kachergius
“THE STROMBERG SPECIALIST”