I'm having problems with a newly installed Stromberg 150CD-SEV on my 1256 Viva. This is the model with an variable height jet using a castellated adjuster - the one you can adjust while its running, but burn your knuckles on the exhaust while you do it! It was supposedly NOS and seems unused, although fitted with an odd, incorrect needle. Using needles recommended by Burlen, firstly B1EU then B1DV, which is listed by Haynes for the 74-5 model, the engine starts and ticks over OK but stalls on any significant load. With the CO set around 3.5% the engine stalls when piston lifted. Even progressivly richening the idle mixture to about 8% CO, engine speed still drops when piston lifted and the engine still stalls under any load. (The plugs start fouling up with a tickover mixture this rich which doesn't help). I'm using an old analogue Gastester and can see the CO drop instantly with increasing rpm.
As the basic fault seems to be fuel shortage under any sort of load, after changing the (rust filled) filter and blowing through the pipes back to the tank without improvement, I bypassed the fixed fuel pipe with clear plastic hose and coupled up my (fake Facet) electric pump and the old mechanical one in series giving 5psi at the carb, so I'm satisfied there's enough petrol available!
I've checked for inlet air leaks but nothing apparent.
There is one odd point. All the literature I have seen says the base of the needle must be flush with the bottom of the piston but mine seems a bit proud - its not adjustable in any way though.
Any ideas would be welcome.
Mike