Stromberg carby

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Submissions by Jacks

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Stromberg Carburettor:

Stromberg Carburettor on a 202 UC. Note that the throttle return spring has been relocated to under the EGR bolt and that a twist has been made in the Throttle Return Spring Bracket. This avoids the problem of the Bracket's original location which was under the nearside Carburettor Stud. Repeated activation of the Throttle twisted the Carburettor Stud loose and eventually tore it out of the Inlet Manifold.Click to Enlargen. Photo by T.

Stromberg Carburettor Tuning & Trouble Shooting Tips:


Bendix Stromberg Single Barrel Carburettor:

Stromberg Carburettor. Photo by Stock EJ. Click to Enlargen.
Failed Lead Slug in the Accelerator Pump Circuit. Photo by Ashmaaaan. Click to Enlargen.


HQ 173 Stromberg Carburettor and Choke Connections. Photo by RedSeat. Click to Enlargen.

Float System:

Image by T

Useful information:

Mainly used on L6 engines, 173 cub ins or 202 cub ins
M = Manual
C = Automatic
BM 173 & BA 173
BM 202 & CA 202
Float Level Settings
Fuel level should be from the top surface of the float chamber, and it should be between 5/8��? to 11/16��?
To correct this
Bend the float arm then re-check the fuel level.
Accelerator Pump
Measure from top of the pump piston stem to the top of the carburettor body, with the gasket removed.
Dual Stromberg Carburettors. Click to Enlargen. Image by CAM570.

Then measure again, difference should be, the length of movement is between 7/32��? to 9/32��?
Vent Valve
This can only be done if the accelerator pump stroke is correct, and throttle in idle position say 500 rpm
Valve to seat opening .060��?to.050��?use a piece of wire/drill to enter the gap between the seat and the valve.

===Idle Setting:===

500 rpm
This is done with the idle screw, and the engine at operating temperature, with the air cleaner on the carby
With Trimatic, wheels should be chocked and transmission in “D��?
Set idle speed around 500 rpm, then turn the idle mixture needle valve until the engine runs regularly
Next turn the idle screw out until engine begins to “roll��?
Then turn idle screw inwards, slowly until the engine is running smoothly
Now reset the idle speed to around 500 rpm
You can then re adjust from there again for any slight adjustment if necessary
Turning the idle screw in “clockwise��? is lean and out “anticlockwise��? is for a richer mixture
Using Vacuum Gauge
Remove plug from inlet manifold and connect the gauge in its place.
Run engine speed to 480-520rpm
Adjust idle mixture to the highest steady vacuum reading, it should be around 18-and 22 inches
Repeat to adjust for fine tuning.
Remove the Vacuum gauge.
for further tips on Vacuum Tuning search in "Holdenpedia"

Two Stage Power Valve (left) and  Idle Tube (right) from HX, LX, HZ, VB Stromberg Carburettor.  Earlier Single Stage Power Vlaves were similar but did not have the Pin Hole on the left side. Click to Enlargen. Photo by XT5.


CARBURETTOR Bendix-Stromberg Single barrel downdraft
ENGINE 161 & 173 186 & 202
Model BXUV-2 BXV-2
Venturi diameter 1.094in 1.15in
Float level 5/8in - 11/16 in 5/8in - 11/16in
Fuel needle seat orifice .073in dia .073 in dia
Flange size S.A.E. 1 ¼ in. with 1.31 in dia. Bore S.A.E. 1 ¼ in. with 1.44 in dia. bore
Main discharge jet No 28-30 No 28-30
High speed bleed No 70 drill No 70 drill
Main metering jet 0.055in & .060in (for 173) 0.055in & 0.065in (for 202)
Power by- pass jet No 56 drill No 55 drill
Accelerator system
Pump by-pass jet No 56 drill No 56 drill
Pump discharge jet
No 72 drill No 72 drill
Pump capacity 5-8 c.c. per 10 slow strokes 5-8 c.c. per 10 slow strokes
Pump link setting Middle Middle
Pump stroke/travel 7/32in – 9/32in 7/32in – 9/32in
Vent vale /adjustment .050in - .060in .050 in - .060in
Idle discharge hole (lower) No 56 drill No 56 drill
Idle discharge hole (upper) No 64 drill No 58 drill
Idle discharge hole (upper) No 70 drill
Idle tube No 68 drill No 68 drill
Idle air bleed No 53 drill 0.054in
Idle screw 1 turn out (approx) 1 turn out (approx)
Carburettor high altitude modification
Main metering jet .053 in (4000 –m 7000ft) .057 in (4000 – 8000 ft
Main metering jet .051 in (8000 –m 12,000ft) .055 in (8000 – 12,000 ft)
The above specification should be right, but if you can see a mistake then please rectify.
Trouble shooting "Tips"
Uses a lot of fuel
Engine tuned incorrectly
Dirty air cleaner
Float level not right
Vent valve needs adjusting
Check idle
Leaking power valve
Fuel leaking
Sticking controls
Engine dies will not idle
Adjust idle mixture and throttle stop
Air leaks from manifold
Low speed jet or idle passage blocked
Engine dies under load
Fuel filter on riser in pipe incorporated
in the fuel gauge in the tank is blocked or
Engine misses when accelerating
Dirty or burnt Distributor Points
Accelerator Pump Valve is sticking or leaking
Accelerator Pump Piston worn out
Power Valve stuck in the up position
Accelerating pump jet blocked
Check spark plugs/setting
Engine needs a tune
Sticking or burnt valves
The Engine Cranks But Won't Fire After Standing For a Week or Longer
The plugs in the bottom of the Float Bowl
(Main Jet and Float Bowl Drain)
are dripping and need tightening.
Can also be caused by incorrectly fitted
Copper Washers under those plugs.
The Copper Washers must be inserted into
the carburettor first, then the plugs screwed
in after them to form a cold weld.
Do not put the washers onto the plugs.
I just diagnosed and solved a classic Power Valve problem in the Stromberg Carby on my UC (gagging on take-off, hunting under level cruise, rough idle).
In the top of the Power Valve Piston there's a crimped Welch Plug that's supposed to seal the top of the Power Valve Piston.
The Welch Plug broke loose and created an air leak. T

Lead Plugs on the outside of the Carby can also work loose and need retensioning. Photo by Jacks.
Alloy washers are used with the Power Valve and the Needle and Seat. Copper washers are used with the Blanking Plugs Photo by BIJ.

Lead Plug Missing From Accelerator Pump Passage:

For the record, I repaired my carby by filing down a sinker until it was slightly larger than the hole and tapping it into place with a punch. It has sealed perfectly. Cheers Mike

Stromberg Carburettor Kit Information:

Info added by HZ Cambridge FUEL MISER CARB KIT INFORMATION Be aware there are two different single barrel stromberg kits. The way to tell the difference in the carbys is the number of bolts holding the top of the carby on. At the front of the float chamber there are 2 bolts(1 in each front corner) on one version. This kit is SB652. On the other there are three bolts, the same two as the two bolt version and a third in the centre of the other two( so in the centre front of the float chamber) and it is slightly forward(when fitted to the motor) than the two outer bolts. This kit is SB655. These are FUELMISER numbers. Having said that most parts in the kits are the same though. From memory the original date for the change in carby was 6/76, When ADR27A was introduced. End of HZ Cambridge' submission  

Stromberg BX Carburettor as used on HX, LX, HZ, UC, VB 6 Cylinder Holdens. The Circled Connection causes the Float Chamber to breathe through the Cannister. This replaces the Accelerator activated Valve that was used on pre-emission Holden Sixes. Photo by Faust Fuhrer. Click to Enlargen.
Stromberg BX Carburettor as used on HX, LX, HZ, UC, VB 6 Cylinder Holdens. Emission Connections shown. Photo by Faust Fuhrer. Click to Enlargen.
Stromberg BX Carburettor as used on HX, LX, HZ, UC, VB 6 Cylinder Holdens. The Slow Idle Screw is centre left. Photo by Faust Fuhrer. Click to Enlargen.
Dual Stromberg Carburettors on a 186 in an HR.  Photo by Farmingoldholdens. Click to Enlargen.
Dual Stromberg Carburettors on a 186 in an HR.  Photo by Farmingoldholdens. Click to Enlargen.
Stromberg Throttle Connection. Photo by Brhill135. Click to Enlargen.
A Bug was found in the Needle and Seat causing Power Loss under Wide Throttle. Photo by oldhzdude. Click to Enlargen.
Main Jet in a Stromberg Carburettor. Photo by RedB. Click to Enlargen.
The photo shows the throttle activated breather valve on the carb top connected to the accelerator pump. The valve closes when the throttle is pushed and is open at idle. Photo by 2HQueues. Click to Enlargen.



Failed Accelerator Pump Circuit Slug Thread

Jacks sheds  



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