So I pump the pedal 3 times and she turns over and over eventually she fires up but as soon as I put my foot on the gas she cuts out, I have to repeat the above process then when she starts let her tick over for a minute or 2 then ever so gently add some gas, too much and she cuts out again, once I get her going she’s fine, any ideas Bazza
It's just the cold Bazza , ITC's don't have a choke so take longer to warm through this time of year .... Sent from my SM-G960F using Tapatalk
I have a Brosol 34PICT-3 kicking around that solves all that stuff... Wind out the mixture screws a bit. Then wind them back in in March.
I think they all have slightly different starting regimes, but similarly to you Bazza, I slow pump 3 times and then do 2 quick pumps and crank as I release the final one. I don't touch the accelerator untill the engine catches (thereby maintaining the vacuum) this may take one or two attempts at the sequence for them to start. Sometime they cut out after starting as well. But as Lasty says, they don't like the cold. I've thought about some sort of small heater pad to wrap the manifold to preheat them prior to starting to avoid the fuel condensing on the cold metal. I must try that out.
Another lateral thought based on my experience with a too- lean idle (mixture screw too far in) which is one of the things thats happening here .. is that if you have a distributor like a 123Tune you can set the timing advance curve to e.g. 12 degrees at 500 rpm, 7 degrees between 700 and 1000 rpm and so on. Then as the engine slows to a stall at idle, the timing advance increases which tends to speed up the idle.. Although in the extreme the engine almost stops, kicks back into life for a bit, slows and kicks if you get the low speed timing advance too brutal.
It's a bit of heat in the heads that's needed if you don't have chokes - usually mine all kick in quite quickly even when it's cold and warm enough in 20-30 seconds to idle nicely if a bit slowly. If you can be arsed it helps winter cold warm up if you fit bigger idle jets.
Weber did several versions of ICTs, Baz. Are you sure you've got the Cockney ones? They're covered in pearly buttons.
I might need to service mine. A couple of days ago after a very cold night a couple of cylinders refused to kick in even after 10 minutes of random revving, holding revs up a bit, letting it slowly idle on 2. Possibly would have been ok if I'd just driven it but there was ice even inside the windscreen so that wasn't a good idea. Eventually I gave up, had a cup of tea and tried again. By then heat soak from the running cylinders had spread to the cold ones and off it went - perfect. Until those cylinders fire all we're doing in this weather is pumping more cold air through them and cooling the next door one too. That's my theory anyway, I'll call it the cuppa theory - much like a flooded engine which perhaps those cylinders were though you'd think 3,000rpm would clear them.
That's why I'd been thinking of the idea of getting some heat to the manifolds...how water bottle, electric blanket, flame thrower?
I don't think it would help personally, they'd cool down again very quickly. A head heater would be more use IMO. Once it fires I can watch the heat rise via the head temp gauge in a few seconds.
Thinking about the reasons why cold weather causes poor starting, I've always assumed it is the fuel vapour from the carbs condensing on the cold manifolds before it gets to the heads. Is this wrong and would heating them work? From a practical point of view I could stuff a hand warmer next to the manifolds to try my idea out
Try it. Mine does fire right up after 3 squirts of neat fuel via the pedal though, it doesn't appear to object to neat wet fuel when cold. It's once it's running the problem I had started. The only time it did this previously I had tiny idle jets fitted and even constant pumping on the pump jets wouldn't keep it running. In conclusion, stone cold it simply wants a heap of fuel in any form to fire a few hundred times and warm the heads a bit. After that it's happy. But - who knows - perhaps there was condensation inside the distributor cap - I didn't look. Heat soak might have cured that rather than warm the heads. I'll look if it happens again.
You used to be able to buy little electric blankets for your inlet manifold called IMDU or something. They were pretty useless tbh
Somewhere in the depths of my garage I have a Scandinavian sump heater. It fits in place of the bottom plate on a type 1 engine. I don't think I'd dare connect it to an electricity supply though given its age
I used to have a 2.3 Opel Blitz diesel motor in a CF crew cab. Spent loads and loads on trying to get that thing to start in the cold but he wasn’t having any of it when cold until I fitted a six or seven K W shower unit and a central heating pump under the passenger seat and bang it on to the mains for twenty minutes before I went off to work. Great so long as I could park on the job near enough to get a 240 lead to it to go home or I was pushing it. Never ever got to sort thing out completely, rebuilt motor, several different starters two a hundred plus batteries and never ever sorted it. Maybe a more modern lighter oil would have helped a bit. Ozziedog,,,,,,,,,,lots of failings today on here
Thanks everyone So it seems as if a lot of you have a few issues with these carbs regarding cold starting and it’s just the norm, roll on the spring
I run 34s Baz and don’t have a problem and never have once I’ve sorted whatever the las test issue is be it overfueling which is every other year or weirdly poor fuel pumps which is nowhere near as frequent. The two things I’d look at and the first it less than a minute per side, is the idle jet, just make sure they are cleared out and a very slightly larger one wouldn’t hurt. One carb will just need a small screwdriver and one carb may need popping off to get to it, some do and some don’t. And while you got them off, both together, hold them up to the light together and look through the holes. Recently I’d replaced mine and only one had the correct drilling and one was either marked wrong or drilled wrong and I could not get that to idle nicely. Other thing might be to check your fuel pressure by taking your fuel pipe off where it hits the T and lay it in a 1L or 2 L empty water bottle and disable the engine spark so it don’t start and get your glamorous assistant to crank it over for you while you hold the pipe an inch or so in the bottle. This should look a bit like a fourteen year old after watching the first episode of Baywatch. The fuel should be squirting almost to the bottom of the bottle and if it isn’t you’ll have a supply issue between there and the tank some sort of blockage or a wonky ( no a ) fuel pump . Or I’m chatting baloney and it’s because my van lives inside in a garage? Ozziedog,,,,,,,,,,,never had a lacking choke issue
