How do you adjust a su hs4 carburetor?
Alternatly adjust the idle screw on each carb, attempt to set the idle as low as possible (~800-1000 RPM). Adjust until the airflow is *close* to the same at each carb. The engine may now be running rough, just keep the idle speed high enough to keep running.
What does the SU stand for in SU carburettors?
Skinner Union
Herbert Skinner, (1872-1931) S.U. stands for Skinner Union and the first carburettor was made by Herbert Skinner and his brother, Thomas Carl Skinner, (Fig. 3) in 1904, and patented in 1905 (No.
How do you service SU carburettors?
Checking and cleaning an SU carburettor
- Remove the screws to take off the dashpot.
- Lift out the piston and jet-needle assembly, taking care not to bend the needle.
- Loosen the grub screw to free the jet needle.
- Prise off the spring clip on the choke linkage.
- Undo the nut holding the jet tube to the float chamber.
Where is the front carburetor on a su H-4?
Here’s a photo of these Type H-4 carbs “as received”: The front carburetor is on the left and the rear carburetor is on the right. If this were a pair of Volvo B16 carbs, the left one would be the rear carb.
What kind of carburetor does a su B16 use?
Today’s post describes a recent rebuild on a pair of SU Type H-4 carburetors. Although most Type H-4 carbs that I rebuild are for Volvo B16 engines (PV-444s and 544s), this particular pair of carbs came from an MGA.
What makes a SU carburetor different from a Volvo?
Each of the four bodies differs in some manner from all the others. The primary difference in the bodies involves the location of the vacuum tap for the distributor. In both cases, that tap is on the rear carburetor, which makes the front carb differ from the rear carb, and makes the MG carbs differ from the Volvo carbs.
Are there jet diaphragms in the HS8 carburetor?
The HS8 Carburetors are not fitted with Jet diaphragms like the HD6 and HD8 but do have self centering spring loaded needles. The jets are 100 thou diameter as opposed to the HD’s 125 thou. This does not pose a problem however as there is a wide range of 100 thou needles available from Burlen Fuel.
Where is the hex nut on a SU HS4 carburetor?
Note: Type HIF carbs (With integrated float bowl) no longer have the hex nut to adjust the mixture. Instead, there is a screw to twiddle, on front of the front carb, and behind the rear. The screw is connected to the needle seat through a temperature compensated gizmo, which is said to make the carbs more stable.
What’s the best way to tune a SU HS4 carburetor?
The Uni-Syn is much easier to use, and can result in better balance. Alternatly adjust the idle screw on each carb, attempt to set the idle as low as possible (~800-1000 RPM). Adjust until the airflow is *close* to the same at each carb. The engine may now be running rough, just keep the idle speed high enough to keep running.
How much does it cost to rebuild a SU carburetor?
Additionally, there are many competent rebuilders who can bring these carbs back to as-new condition for a reasonable fee–figure $50 to $75 to rebush each carb’s throttle shaft and $350 to $500 to completely rebuild a pair. Polishing all of the external parts can add another $100 to $200 to the rebuild cost.
How does a SU carburetor adjust to the fuel mixture?
Thus, the SU self-adjusts to the air/fuel requirements of an engine. It only flows as much air as necessary, and the tapered needle ensures that a proper fuel mixture is obtained at any air flow. This self adjustment needs a little help at two times: During cold starting and hard acceleration, when a richer-than-normal air/fuel mixture is needed.