Thread: series 3, 2.25 carbie problem

Hi, I've recently bought a "76 series 3 with 2.25 engine. It wouldn't idle properly and the mixture screw was buggered so I bought a new carbie. I also did all the usuall things for a tune up - tappets, plugs, dizzy cap and leads, and fitted an electronic pick up to replace the points and condenser. I also blanked off the air intake under the carbie flange where the crankcase gas thing was mounted. The engine now idles very wel, but when I try to rev it out while driving it the engine sort of "chokes" at high revs and won't give enough power. When I pull out the choke as it is gasping it suddenly picks up and revs out as it should, indicating I think - running lean. I have sprayed water around the carbie joints and inlet manifold to check for sucking air while revving it but did not detect any change in engine note. I dismantled the new carbie to check for blockages and also lapped the joints in carbie body before reassembling. Still the same. Only the main jet in the new carbie had a number on it and it is the right one. None of the other jets have sizes on them.
I'm also not sure about checking the timing with electronis ingnition as I can't check for points opening at TDC (it's 8:1 compression). I put a strobe light on it at the lowest revs possible and set it to TDC. It seeemed a bit gutless so I advanced the timing a bit by guesswork and it seemed to help - with no knocking.
Any advice on these matters would be greatly appreciated, especially the lean mixture problem.
Cheers,

take the rotor cap off and suck on the vacuum advance hose and see that the dizzy plate rotates.

check that the vacuum advance works with the engine running (does the hose have suction at revs?)

check the needle and seat in the carby, maybe the float needs a little adjustment so that it lets more fuel flow in.

from memory tune it to 7-9 degrees advance

the series motors don't ping. My 2.25 would get over 30 degrees advance on throttle. This was okay when they drank super petrol, but now with diet petrol (ULP) apparently it's too much advance. I ran mine on ULP and LPG and an ignition specialist retuned the dizzy to have an advance curve better matching these fuels.