271 starting problems

[Maestro384]

Good evening all I’ve got turbo 271 that was starting lovely but wouldn’t run properly or go onto boost so my good friend Keith who knows his way around these changed a few things and found the fault to be the carb vent valve that wasn’t closing so letting the boost escape
so the pipe has now been blocked off and it runs amazing now and pulls like a train and ticks over lovely without smelling of fuel but the problem now is it’s a real bugger to start now from cold so would it be the absence of the vent valve and would it be recommended to put a new vent valve on it if I can possibly find one

[Jeff Turbo]

This would normally be the O rings that are attached to the stepper motor. The first thing you should change would be those. Also is the small rod coming out when you first put the ignition on as that is also part of the start up process and does it need adjusting where it pushes to enrich the mixture?
The lack of the vent valve wouldn't affect starting from cold but will from hot

[Maestro384]

Yes m8 the rod comes out and the carb has been rebuilt and it’s been stripped and checked in the last 2 weeks just in case it had pulled any crap from the tank with it been stood so long and that’s fine so I’ll get the stepper motor checked

[Jeff Turbo]

Yes m8 the rod comes out and the carb has been rebuilt and it’s been stripped and checked in the last 2 weeks just in case it had pulled any crap from the tank with it been stood so long and thats fine so get the stepper motor checked

If you remove the stepper motor you will see the two O rings, the stepper is working as the rod is being pushed out but the O rings might be letting air in if not in good condition I would also check the clearance gap from the rod to the fast idle position when cold

If anyone wants to check the vent valve is working correctly for future reference
Turn the ignition off and blow down the the pipe through the valve, is should be clear, turn the ignition on and it should now be blocked.
The part numbers for the vent valve are ADU9160 superseded by AUU1128 though both are NLA unless you search

[Maestro384]

Do you think it’s worth putting a new vent valve on if I can find one or does it make no difference

[Jeff Turbo]

Do you think it’s worth putting a new vent valve on if I can find one or does it make no difference

Blocking it off only affects starting from hot. It can be a little difficult so if you experience that then try to find another, either that or have a look at your existing to try and find out why it's not working

[Maestro384]

I think the problem is the car has done 400 miles in the last 16 years and although it’s had mot’s and services and the previous owner spent over £2300 on it 2 years ago by getting new tyres timing belt service carb rebuilt brake fluid flush and so on it’s not done the mileage so it’s done 18 miles since he had all that done and the car had been parked outside for a few years as well so I think the vent valve has seized open through inactivity
so can a vent valve be fixed

[Jeff Turbo]

I think the problem is the car has done 400 miles in the last 16 years and although it’s had mot’s and services and the previous owner spent over £2300 on it 2 years ago by getting new tyres timing belt service carb rebuilt brake fluid flush and so on it’s not done the mileage so it’s done 18 miles since he had all that done and the car had been parked outside for a few years as well so I think the vent valve has seized open through inactivity
so can a vent valve be fixed

Yes I should think the valve can be saved, just a matter of a clean out I assume, reconnect to a power supply, tap it a few times and see what happens as you say it's probably stuck in the open position through lack of use.
This may also be the reason it's not been used as it was causing it not to boost so undriveable. If it's stuck in the open position it's letting air in as i told Keith air was getting in the system somewhere and it seems this was the cause