Fuel pump carb issues

[Steve3283]

    Wow 

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Hi, 

New to this form but I’m hoping that someone can help or at least shed some light. I inherited my 1935 Opel a rebuild with my late grandfather always ran smooth and never missed a beat. I started having curling issues and she just required a new lift pump, once fitted she starts and runs but appears to be over fuelling the carb and leaking fuel from the small overflow hole.

I’ve Stripped the carb (solex 26aic) and the inlet valve was stuck... great easy fix.. or so I thought. Started and ran well however still over fuelling and leaking. The inlet valve. Is a 2.0, i was thinking of looking to reduce it to a 1.5 if I can find one. I know the lift pump is correct bought from the Austin soares and checked so the problem must be the inlet valve right? 

Any thoughts and ideas are welcome, coz it’s driving me mad not having her running 

Thanks steve

["Slack Alice" Simon]

Look back over the Forum a week or two, there was a thread about leaking carbs.

I will repeat what my contribution was: there may be a non obvious leak from the banjo joints, I always use a low strength Loctite type goo that works well as a sealer.

You don't have to over tighten to get a seal.

Simon

[Steve3283]

Thanks Simon I will look at that as it mentions lowering the inlet valve height, my leak is where the arrow is and it just seems like the lift pump is too good for the carbs current set up, but I’m just really not sure

[Nick Lettington]

I'd be interested to know what folk think of the new T-type pumps. I thought I'd read they are a bit more powerful and cause old carbs to leak..? Hence trying to fix up my old one. It runs ok today, but may decide not to at any time.

[David Stepney]

I think the problem lies in the fact that the replacement pumps are based on the 'U' type pump, not the old 'T' type. The pumping capacity is greater.

[morrisminor]

I've tried 2 new pumps and they both made my carb and a friend's leak that was known not to leak, put the old pump back on,  no leaks

[Steve3283]

Right that’s the way the rebuild the old one, just out of interest. Did you send the new ones back? As it clearly wasn’t £65 well spent!

[Nick Lettington]

Or is it possible to limit the pressure somehow... An in line regulator or a spacer on the crank case..? There must be a good compromise?

[David Stepney]

The problem is that replacement bits for the 'T' type pump are non-existant. So, if the pump packs up, we are stuck with a replacement 'U' type pump.

Ruairidh Dunford has expressed the opinion in a related thread that the problem may be in the spring fitted to the replacement pumps being too strong.

I have fitted a replacement pump to my car and the carb (a 26VA) still leaks on occasions, but seems for some unfathomable reason to have largely stopped doing it. Certainly, my carb has never leaked while the engine is running, only when stopped and I have taken the view that I would rather have a running car a dripping carb that a car that doesn't run. However, I might try putting the 'T' type spring into the new pump to see if that helps. I might to that tomorrow.