Not all cylinders firing during cold start, now hissing sound from brake servo

[bambily]

This is an old problem for my 1.9 DG. During cold starts it takes some time until all cylinders are firing. At first the I can feel the engine shaking for some time (minutes?), but after a while the shaking stops and the engine “sounds” better.

I read that the chunky vacuum hose connecting the one way valve and the manifold could get brittle and that could affect the firing, so today I replaced it with a brand new from Brickwerks. At first it started, still rough, but it seemed that it was running to fast. I turned the engine off to go back to the engine bay to make sure the throttle wire wasn’t stuck somehow. It wasn’t stuck but now I can’t the engine to start at all. The starter just keeps chugging.

Any ideas?

[jrt]

Have you flooded it?
I would clean the plugs/ check for fouling/ spark and check fuel delivery.
Check the choke/ pull down and if all vacuum pipes are good.
If all good maybe a drop of fuel down the carb’ and see if it fires.
You haven’t knocked a wire off the coil or summat when you replaced the hose have you?
David.

[bambily]

Sorry if I wasn't clear, I was able to start the engine once after the vacuum pipe was replaced, but just once.

I might have flooded it, I'll try to check all things you mention tomorrow. Thanks for your reply!

[bambily]

Reading up on flooded engine and yeah, the symptoms match. The cranking was much faster than usual.
So, I'll remove the spark plugs first thing tomorrow morning and crank the engine by hand. Should I add some oil down the plug holes to try to re-establish the oil film?

I think I have a new set of correct spark plugs ready for use.

[bambily]

Success at starting the engine! Removed plugs, some cranking by hand, new plugs, cleaned all connections from coil to dizzy to plugs.
Was about to leave the driveway to take it for a spin, but noticed a hissing sound somewhere from the brake servo during braking. The pedal also drops slightly. No change in brake fluid.

I changed the old vacuum pipe to/from the manifold as I suspected it was leaky, could it be that the servo never had to handle "real" vacuum before so some old diaphragm now show signs of leaking instead? Guess I should read up on how the brake servo works as my next step. 

[jrt]

Well you’re getting there.
Does it feel harder to brake? Sounds like a vacuum leak somewhere or as you say the servo may be on its way out.
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David.