26-05-2018, 04:35 PM
Hi,
I have an "Ulster" replica with a 1 1/4" SU Carb from a Morris Minor (I Think) with an AN needle which is fed from the scuttle tang by a 6 volt SU pimp.
I have set the timing to TDC fully retarded, it's a later DK4A distributor, but have always had problems with starting. Mo matter what the weather it needs full choke to have a chance of starting but on the road seems OK. However if you switch off re-starting is sometimes fine but more often problematic.
To try to resolve the starting issues I have dismantled and fully cleaned the carb, re-checked the timing, added fresh petrol, and made sure the float level is correct. However, when I try to adjust the mixture at tick-over I can turn the jet up and down around two turns with no real effect on the running.
The plugs are normally black so it looks as though I need it very rich to get started but then it's too rich for normal running.
The engine was completely re-built by me a few years ago so I don't think there's any problems with compression etc and, as far as I can tell there's no leaks in the induction tract.
Any suggestions why I can't seem to adjust the mixture correctly?
John.
I have an "Ulster" replica with a 1 1/4" SU Carb from a Morris Minor (I Think) with an AN needle which is fed from the scuttle tang by a 6 volt SU pimp.
I have set the timing to TDC fully retarded, it's a later DK4A distributor, but have always had problems with starting. Mo matter what the weather it needs full choke to have a chance of starting but on the road seems OK. However if you switch off re-starting is sometimes fine but more often problematic.
To try to resolve the starting issues I have dismantled and fully cleaned the carb, re-checked the timing, added fresh petrol, and made sure the float level is correct. However, when I try to adjust the mixture at tick-over I can turn the jet up and down around two turns with no real effect on the running.
The plugs are normally black so it looks as though I need it very rich to get started but then it's too rich for normal running.
The engine was completely re-built by me a few years ago so I don't think there's any problems with compression etc and, as far as I can tell there's no leaks in the induction tract.
Any suggestions why I can't seem to adjust the mixture correctly?
John.