Rover Sports Register Forum

Can someone tell me the model of the SU carb fitted to a 1935 Rover 12 ,and is it the normal way of tuning an SU even though its a horizontal model Len

Its a D3 and yes setting the carb up is the same as any other SU carb of the era.

Hello just started to set the carb up.I found the needle adjusting screw was only 3/4 of a turn from fully in ,so I have unscrewed it 2 turns from closed ,the car starts OK but the choke is very tight to pull out .It isn`t the cable as that`s free ,it was quite free before I adjusted the nut

Check the needle isn't bent.

Repair kits should be readily available from Burlen Fuels

Hi Len,

How is the car running? The nut you have undone adjusts the jet, rather than the needle. The needle is attached to the piston, which you can move manually with a thin screwdriver through the Venturi (air filter removed) to check for free movement. Assuming that is free moving and operates easily as you rev the engine, any tightness can only be the jet itself or the cable. Assuming the cable is fine, have you turned the jet at all? After many years working a certain way round it may be tight in it’s seals if turned, say, 180*. Also the seals may have hardened, which may be a problem.

Back to the running; does the jet need to be set two turns of the nut outwards? This will be a richer setting than you originally had and is only an advised starting point. Once the engine is hot, the nut can be adjusted in or out to achieve the best running, ie fastest and smoothest. Then slightly weaken it. This establishes the relationship between jet and needle profile for the entire rev range, so worth getting right.

If your carb hasn’t been refurbished for a long time there could be any number of parts and seals that have become weary. It will still work, but fine adjustment and smooth tick over is difficult. Burlen or Southern Carb can supply an overhaul kit. Worth checking that you have the correct needle and spring too as crucial to correct running. They do those too and not very expensive.

Tony.

I screwed the nut fully in and backed it off about two turns,but the best running is when it is only about 3/4 to 1 full turn out .The engine still seems to be running rich though Also I have a video of the engine running,but when I try to add a file,it doesnt show up on the list of photos on my card Can you post videos on this forum Len

See here http://www.rover-forum.thersr.co.uk/viewforum.php?f=34

When it says you cannot post attachments in this Forum ,why can you add photos but not a video .I have`nt a thermostat in the rad at the moment,will this make a difference to the setting of the carb.The engine doesnt get up to normal working temp,but I thought it would still be possible to set the carb.

Sorry I forgot to add , do you need a thermostat in it during the summer Len

Just started to dismantle carb and the first thing I found,was the fibre or cork washer on the jet assembly broke up.So obviously a time to recon the carb,I`ll order the parts and see where we go Len