Powerplus 2286 with SU carburetter
Discussion
Hi,
got an interesting fault with a 2286 Land Rover, it has a power plus high-compression cylinder head with the SU inlet manifold and an HIF44 carburetter. It ran OK for a while but has recently developed a problem with maintaining a steady idle speed. I have been told that this is because the idle mixture is too rich. The carburetter appears in very good condition, I have stripped it, given it a good clean, and:
checked the float height, 1.0mm
the vacuum advance port is clear
the idle bypass valve on the throttle butterfly is soldered shut
the EGR port is blanked off
the fuel pump is new
Unrelated to the carburetter I have:
fitted Lumenition (and converted to negative earth)
the vacuum and mechanical advance works correctly
the leads, distributor cap, rotor arm and 'plugs are all newish
I have changed from a BGB needle to a modified BAK (purely as a means of verifying that the idle mixture is too lean. With the BGB needle I had the mixture screw all the wound way in and it still wasn't rich enough. Now the most drastically modified needle has a base diameter of 0.085" for about the first three or four stations. The engine now idles OK when cold but my Dad gave it a run and the problem returned when it is warmed up.
I am lost for solutions, other than ringing the supplier and my carburetter contact for advice in the morning.
Am I missing anything obvious?
HELP PLEASE!
got an interesting fault with a 2286 Land Rover, it has a power plus high-compression cylinder head with the SU inlet manifold and an HIF44 carburetter. It ran OK for a while but has recently developed a problem with maintaining a steady idle speed. I have been told that this is because the idle mixture is too rich. The carburetter appears in very good condition, I have stripped it, given it a good clean, and:
checked the float height, 1.0mm
the vacuum advance port is clear
the idle bypass valve on the throttle butterfly is soldered shut
the EGR port is blanked off
the fuel pump is new
Unrelated to the carburetter I have:
fitted Lumenition (and converted to negative earth)
the vacuum and mechanical advance works correctly
the leads, distributor cap, rotor arm and 'plugs are all newish
I have changed from a BGB needle to a modified BAK (purely as a means of verifying that the idle mixture is too lean. With the BGB needle I had the mixture screw all the wound way in and it still wasn't rich enough. Now the most drastically modified needle has a base diameter of 0.085" for about the first three or four stations. The engine now idles OK when cold but my Dad gave it a run and the problem returned when it is warmed up.
I am lost for solutions, other than ringing the supplier and my carburetter contact for advice in the morning.
Am I missing anything obvious?
HELP PLEASE!
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