Old time mechanics.L200 carb issue

Calling all the old timers for a bit of advice as to what might be causing what seems to be a flooding and/or overfueling issue in a 1990 L200 2.6 Astron. Symptoms are hard starting mostly when hot. Hold foot hard down and she winds over for a good 10 seconds before firing. Puffs of black smoke occasionally. Cold start not so bad but still needs a bit of throttle and appears the choke is not functioning as it idles low when cold and spits black soot or unburnt fuel out of tailpipe. When revved there's a heap of black smoke and she's rough for a few seconds then clears.

Runs absolutely fine on the road and idles perfectly when hot. I have no intention of messing about with this myself as a quote from a good mate of my Dads years ago comes to mind. "The only thing wrong with carbs are the people who try to fix them "

So will be outsourcing this job to the pros but thought what the hell, cant hurt to get some opinions first. This is not doing the starter motor any favours so would be handy to sort it.

choke vacuum pull off valve. disconnect hose and suck on it. it should open choke a bit when choke is closed. also check water hoses for choke. they get blocked. and dont allow coolant circulation. if choke valve ok. adjust choke WHEN COLD. theres a small dot and line to be lined up. undo small nut. 8 mm spanner and screw thread in .till they line up. must be done dead cold.

I'd be having a look at the water pipes at the base of the carb (thats if this model has them). Most old Mitzis those pipes are well blocked up with green crud. You really need to take them off and blow them and the stubs they fit on out with comp air.
If you want to try be very careful. At this age the stubs are likely to be very fragile.

Unless someone has already messed with the auto choke settings then they shouldn't need to be touched at all.

Also check the engine thermostat. Is it running at correct temp as if cold the auto choke will be in the on position all the time.

"Old time mechanics"
"1990"

Hubby says GGGGRRRRR "1990 old time" ? Huh !

Fuel shut off solenoid?

*snap*

What's this "carb" thing you speak of?

Thank you for the helpful replies, that gives me somewhere to start looking.

Hubby can grrrr all he likes. Fact is a 1990 really is about as basic mechanically as anything from a decade or two before. Vastly different to any of the newest stuff

Be careful of those hose fittings. as has been said, they will be brittle and corroded by now. Probably best just to check there is hot water getting through them by holding them both after a cold start and checking they both warm up together.
And if this carby is a plastic bodied one. don't try getting the top off yourself. the gaskets are strong enough to break the plastic sometimes.
It might be a diaphragm which is accessible from the outside anyway.
Check the choke operation and that it's getting pulled off properly once the engine starts. There will be a manual available online somewhere if you want to try fixing it yourself before sending it off to the experts.

L M A O
Well incidentally the ole asian carbs of dat era were from the factory with the ole **factory faults** And yes twas well -a foray in to emission control- LOL
The choke vacumm break spoken of had a vacuum diode fitted to it.
Alas. back to front from the factory.
[. When revved there's a heap of black smoke and she's rough for a few seconds then clears. ]
One side of the diode will give resistance to suction-the other side will suck easily.
Inherent design was to use the lack of suction side to hold the choke vacuum break open.
{When fitted back to front from factory it had the . overchoke you describe-as in lack of vacuum transmitted to the choke break}

Also they pulled a whole bunch of vacuum advance fittings (with small hole) and used them to provide vacuum to the second throat actuator.
Lazy and gutless-untill drilled out

Thanks mate, will do that test first, but at least now I have an idea of what may be causing it. I might have a bit of a look but I don't want to f**k anything up. This water hose business, is that a common thing or was it unique to Mitsis of the era?

Great knowledge, thanks mate. I'm learning, but still hesitant to touch it lol. It goes at the moment. I would like it to stay going which is why I'll probably get the pros in haha. I'm no carb expert so if I mess with it, it could end up worse off than before lol. But I will have a look at a couple of these basic things guys have mentioned. Carbs are just one of those fickle things that best left alone unless you know exactly what you're doing.

I'm having trouble remembering exactly what that car has on it Shreddies, but I suspect the water heating is to get the carby itself up to temp. I think the choke is electrically heated to make it come off. It might be water heated though.

You should check when it's cold and the engine isn't running, that the choke butterfly is closed, and then, that it gets pulled back as soon as the engine is started. If those two things are happening then the lack of reaised idle speed when it's cold is because someone has adjusted the wrong screw while trying to adjust the normal warm idle speed. There is a screw for the idle speed, and another for high idle speed while the choke is on. People muddle the two up.
If the choke is coming on, and first "unloading"(that'-
;s the diaphragm pulling the butterfly open), then slowly coming back to the open position after it's warmed up(you check this by turning it off when it's warm and the choke shouldn't close), then the choke is operating properly.

Then the possible causes of richness would be an external diaphragm )or perhaps internal plunger), which operate something that enriches the mixture when you put your foot down hard. That's called either a power or economy jet depending on how it works. Or it could be another diaphragm that operates a small pump when you open the throttle quickly. You can check that second one's operation by opening the throttle quickly with the engine off while you are looking down the carby. you should see a squirt of fuel come in from the side. If the diaphragm is holed then the pump won't work but the fuel will go through the diaphragm all the time and in via a vacuum drilling to the engine. causing it to be rich.

I think those are about the only simple things you can check visually and without much dismantling.

You say it idles well and so it's probably not it, but it could also be the float level is too high. To check that is fairly simple I think. you take a bung out of the bottom of the carby and screw/wind a bit of plastic tube in tight enough so the fuel won't leak out. then you run that hose up the side of the carby bowl where there should be a cast line on the side of the bowl. When the engine is cranked over or started the hose should fill up to the level of that cast line.

If none of those checks reveal anything. off to the experts I think.

So, there are I think three diaphragm on the outside of the carby, one to unload the choke, which will leave the choke on if it's holed, and two others that can let fuel into the engine if they are holed.
If the choke one is working, which is an easy check, then suspect/examine the other two.

That's absolutely fantastic info, thank you so much mechnificent. I'll print off this page and do as much as I feel confident, and if no joy will get it looked at.

Aside from the odd smart ass this board remains one of the best for gathering any motoring related info.

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Zee round plastic doofery in zee piccy on da right is zee sucker zat ya suck through it oneee way and suck through it zee other way.
And ONE WAY ONLY
Is an EASY suck.
Green one end one rubber vacuum hose either side
Marked A and B on either side And black and well green
or black and red
black and yellow.
lol Still marked A and B