Strombergs leaking fuel into inlet manifold when not running

[PeteG]

Just rebuilt my carbs, i have not replaced the needles or jets, but new fuel float level valves, gaskets, diaphrams etc. My problem is that it constantly floods after its been standing with engine off. So wont start.
When i take carbs off the inlet theres a pool of petrol sitting at the bottom of the inlet , hence why i suspect poor starting is down to flooding.
i have adjusted the floats to 17mm and im getting no no fuel from the fuel drain pipes.Pump seems to tick very slowly.
Im starting to think its the jets needles allowing fuel to rise into the carb body when engine off. Should the needles block the syphon tube into the fuel resevoir when fully down, ie engine not running.

Any advice would be much appreciated.

[trunt]

If all is OK the fuel level in the float chamber is below the top of the jet orifice so fuel will not flow into the carb, when running the fuel is drawn up by the vacuum.

the float level determines this and when the floats get high enough they shut the fuel off with the needle valves. I would guess that the valves are faulty, so fuel is still entering and flooding the carb. Probably no overflow because it’s too slow and it all goes into the carb. It would also tick if they are leaking..

I would check your needle valves..

[Lingen]

Pete.
Take the tops off the carburettors, then lift out the pistons and diaphragms so you can see to tops of the main jets.Turn on the ignition and wait to see if fuel starts dribbling out of the jet(s) into the manifold. If it does, then there is a problem with the new fuel inlet needle valve(s) . If the fuel hoses are starting to perish, it may be that when you refitted them, bits of rubber from the inside of the hose may have got shaved off and got stuck in the valves. If they are clean, then sometimes giving the needle a sharp tap or two with a small hammer might make them seat properly, and stop leaking.
Mike.

[Matt Cook]

Is this a new issue, are you running the original fuel pump or have you changed the pump recently? Could be high pump pressure pushing past the valves. I’ve fitted a filter king filter regulator and set at 2.5psi I think. Those needle values don’t hold much pressure
Matt

[DJT]

I believe there are some faulty fuel chamber gaskets around which foul the float, stopping it from operating the inlet valves.

[PeteG]

Hi Gents

Thanks for the suggestions. To update i did remove the carbs and set them over a bucket and turned ign on. Fuel poured out, Opened up the float chambers and fuel was leaking past one of the valves. Sorted, refitted and retested. Now fuel pouring out of the lower jet orifice on both carbs. Increased the float height to 18,mm. (i know it should be less). Re assembled and no more fuel. Refitted carbs and started on full choke no issue. Them allowed to warm, balanced air flow and runs good, but needs choke to start even when warm. I guess i have over done the float height so too lean. Engine has just had a full rebore/regrind so and have read its best to run it lean and richen as it beds in. Will probably put colour tune on and adj needles before messing with float level jus in case.
One other issue is a small coolant leak from the left transfer housing at back of head, Struggling to get spanner on it to tighten, guess this is just another perciverance, job, i will flatten out a ring spanner end in the hope it helps.
Also sprayed Hard top up the other day so next job is to fit glass, headlining and trims, Not looking forward to it, wish me luck,

Cheers

Pete

[Jeff]

One other issue is a small coolant leak from the left transfer housing at back of head, Struggling to get spanner on it to tighten, guess this is just another perciverance, job, i will flatten out a ring spanner end in the hope it helps.
Pete

Have you tried small 1/4” drive ratchet and socket ? Also bear in mind there is a fifth bolt hidden in the centre of housing !