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DB18 Carburettor Flooding

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Johnsson
Posts: 55
Joined: Fri Feb 12, 2016 11:23 pm
Location: Brisbane, Australia

DB18 Carburettor Flooding

Post by Johnsson »

My car often sits for a long time and the carburettor bowl dries out. When this happens the float bowl arm and the needle valve jam in the open position so that the carburettor floods when I start the car again. I am thinking that if I bend the float bowl arm I may solve the problem. I realise I then have to set the lower part of the arm to give the correct fuel level in the carburettor bowl when full.Has anyone else had this problem and how did they solve it?

Trevor

A.N.Other
Wide Man
Wide Man
Posts: 551
Joined: Tue Feb 16, 2016 12:45 pm
Location: Leeds

Re: DB18 Carburettor Flooding

Post by A.N.Other »

I seem to remember that there is a setting on the SU carb for the arm that operates the needle and float relationship. I remember setting it with a drill shank on my first SP. I may be well out but seven sixteenth’s rings a bell. It may be worth checking as if it ain’t right it may be dropping too far.
Colin,
I may be slow but I’m rough as well !

User avatar
captain bobo
Posts: 268
Joined: Tue Feb 09, 2016 7:32 pm
Location: Kimbolton, Cambs

Re: DB18 Carburettor Flooding

Post by captain bobo »

I can refer to my SU carburetter service manual if it helps for the relevant dimensions. However, I'd need to know the SU model number.
Best wishes, Dave B

Peter Grant
Wise Man
Wise Man
Posts: 503
Joined: Thu Mar 10, 2016 10:02 pm
Location: Sydney, Australia

Re: DB18 Carburettor Flooding

Post by Peter Grant »

Hi Trevor,
Why not just start the car up regulary to,keep fuel in the bowl or just prime it with the fuel pump?
Cheers
Peter Grant

Sydsmith
Extremely Wise Man
Extremely Wise Man
Posts: 1369
Joined: Sun Feb 14, 2016 11:15 pm
Location: Aberystwyth Wales

Re: DB18 Carburettor Flooding

Post by Sydsmith »

Hi Trevor. I may be barking up the wrong tree but I had the same problem with my SP250.

It stood for a year during some family problems, I started it every few months and the float valves stuck, when I stripped the carbs down both valves were sticking because there was a sort of soft corrosion on them. I cleaned them off and they worked OK till the next time.

I put it down to what goes for modern petrol.

When I bought the car it came with a large bottle of Redex which ran out, I have since started using it again and have had no further problem.

Might be the answer to your problem, but I have to say my V8 250 has never suffered the same problem.

Johnsson
Posts: 55
Joined: Fri Feb 12, 2016 11:23 pm
Location: Brisbane, Australia

Re: DB18 Carburettor Flooding

Post by Johnsson »

Now I have the car running again I tackled the problem of the flooding carburettor. At first I tried bending the arm that controls the float valve.That didn't work. Then I bought a new valve but that made it worse as the valve was smaller in cross-section than the original and kinked worse. Finally I got hold of and old carby from a friend and swapped both the valve and the float, reset the arm and solved the problem. I think the problem was either the float (although the old one seemed okay) or the rubber tip on the old valve that had been affected by modern fuel. The replacement valve has a metal tip.

Trevor

Mark Bullen
Posts: 219
Joined: Mon Feb 15, 2016 1:07 pm
Location: Wiltshire

Re: DB18 Carburettor Flooding

Post by Mark Bullen »

I had a similar flooding but it happened when running, I initially thought it was the arm but resetting made no difference.

I then replaced the needle and seat, as there was wear on the needle, no improvement. I then re-adjusted the setting arm (as per the manual). This failed to cure the problem.

It was finally traced to the float being full of fuel.

A replacement float, arm and pin, then correctly set (with the new needle and seat seems to have cured the problem. Burlen Fuels provided all the bits and their website is great for instructions. It also allows you to enter the type of car so you can ensure you buy the correct parts.
Hope this helps?

Mark

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