carburettors are losing oil - is this a common problem ?

[Dazza the Stag]

Evening all

The stag had its mot last Saturday and also had the oil in the carbs topped up as they were dry and causing running issues.
Anyway took it out again last night and the same issues had returned and the carbs are dry again. The diaphragms were both checked and are ok.

i don't really understand the make-up of the carbs and am not too sure what / where to check first.

Any suggestions please

thanks

Dazza

[DJT]

Dazza,

Inside the carb pistons are the needle carriers. These have small o-rings to prevent oil loss. Your have no doubt gone hard and are leaking. It is a fairly straightforward job to replace them.

[Dazza the Stag]

Thanks dave - would it be these from ld parts ? I would rather get them before I take the carbs apart



Carburettor Compensator Seal Small 516971
£1.47 INC VAT


Carburettor Compensator seal Small Size

[DJT]

No, those are for the temperature compensator. These are the ones:

http://www.ldparts.co.uk/shop/shop.php?c=viewproduct&pid=57&cat=26&maincat=1&start=36&sid=sid8b19953e85f4ac27a56860d6260ea912

They fit on this part:

http://www.ldparts.co.uk/shop/shop.php?c=viewproduct&pid=765&cat=26&maincat=1&start=36&sid=sid8b19953e85f4ac27a56860d6260ea912

http://www.stag.org.uk/technical/index.htm

Pages 51 & 52 explain the job

[MandM]

006.jpg
this may help it's the seal as Dave said above the needle on the brass thread screw, hope this is helpful.

[Dazza the Stag]

Thanks guys - that article is just what I need. It mentions a needle adjusting tool - is this something special/essential or can it be done with a more common tool ?

dazza

[DJT]

http://www.ebay.co.uk/itm/STROMBERG-CARBURETTOR-MIXTURE-ADJUSTING-TOOL-/371061497923?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5664fd2043

http://zenithcarb.co.uk/carb-adjusting-tool.html

[wilf]

Thanks guys - that article is just what I need. It mentions a needle adjusting tool - is this something special/essential or can it be done with a more common tool ?

dazza

Dazza - essential. The tool turns the needle adjusting screw (with an allen key) whilst stopping the airvalve assembly from turning (which can rip the diaphragm).

[Dazza the Stag]

Thanks for all the comments so far, thanks to Peter at ldparts I now have the tool and the seals as described above in super quick time. One last question before I try this the article talks about the needle returning to its datum position, and I'm not really sure what that means. Essentially if I take everything apart am I am able to simply put it back again without needing any knowledge about adjusting the carbs ? Or in other words does removing these parts upset the running of the engine, the reAson I am nervous about it is the fact of needing the adjustment tool - I don't really want to adjust anything, I just want to get at that seal.

it might make more sense when I open it up but I do like to have an idea of what I am doing before I start !

thank you

[DJT]

Darren,

If the carbs are adjusted fine now, then the best thing would be to check where the Delrin washers are relation to the bottom of each piston. They should be flush, or close to it. When you reassemble, adjust the needles so that they return to the same position. The manual explains how to set these up as a base setting (flush) then adjust either way to get the correct mixture. It isn't difficult, but if you aren't happy having a go, I'm sure there will be someone close who will help.