Stromberg CD150 issues

[thebrookster]

From the start:

MOT was out and I had been having continued running issues with my Mk1. A couple of months ago I purchased some rebuild kits.
Now, just come back from my last work assignment, so I rebuilt the carbs. Discovered along the way that throttle spindles were goosed, so also ordered new spindles and plates. Tried to run the engine, and found that the Huco pump had died.

Now, new fuel pump has arrived, and been fitted. Engine run and carbs roughly dialled in.

I discovered that neither carb was happy, so whipped them off and opened the float chambers. Turns out the front carb has a different style of chamber which does not fit the gasket supplied. Not only that the gasket from the kit was jamming the floats shut, so no fuel. So, new gasket fabricated, all working.

Rear carb - Again I had to trim the gasket as it was catching the floats, so they weren't closing, causing the carb pour fuel everywhere. Took the car for a brief spin to check how everything was, after a mile or so I lost power. Pulled into a side, and when I pressed the clutch the engine died. Opened the bonnet to find the rear carb again pouring fuel out through the overflow/breather. Removed and opened the carb again, nothing obvious. Fitted it all back again, started the pump and still pouring out. This time however the engine started, and once running the overflow stopped.

I am not running any huge pressure on fuel (pump is a Huco suction pump running at 1.4 psi).

Anyone got any suggestions as to where I go next? (And believe me, EFI is starting to look very promising!!) For a simple carb these are becoming a bit of a nuisance. Rebuild kits I got were official Zenith kits (CDSK 11 for 125/150CDS, GRN No. 32115, however so far I have had following issues:

Diaphragms too stiff and not allowing pistons to fall to bottom position properly, I ended up re-fitting the old (except not so old) diaphragms which were softer.
Wrong gasket (though this may well be a bastard carb issue!!)

Cheers,

Phil

[johnnydog]

Having had the exact same symptoms of fuel pouring out of the breather after I rebuilt my carbs on two cars, I found the problem was with the new needle valves. It appears that even new Zenith needle valves don't seat adequately, causing over fuelling, and the excess pours out of the first available orafice! I ended up fitting a used pair from another set of carbs, and the problem was solved.
I have outlined my issues with over fuelling of Strombergs following a rebuild in previous topics, so a search should give you all the info you may need about this.

[Simon2000]

I had to replace brand new needle valves as the new ones kept jamming ans flooding - I complained to Burlen and sent me ones with mesh filters and a different pin design and seem much better design and less likely to stick. They said they had no complaints\returns on the original type, which I find hard to believe, CW said he stopped stocking them due to issues.

These are the ones they sent me:
http://zenithcarb.co.uk/catalogsearch/result/?q=B24008

They have been fine since fitting.