Help needed.

Here you go, Harvey's old carb complete with a bit of stray overspray:rolleyes:

The tick-over adjuster is arrowed.

 
It's possible that the tick-over screw could have backed off a bit, as you screw it in you should see the linkages move slightly.
 
Mr P. Is this the same screw to adjust timing as to adjust tick over...

As you know I have a dead spot in the low revs so I brat inertia at a roundabout but then have a real (embarrassing) lag before the van pulls forward and accelerates. Worse still on the hill out of Knutsford where I was in first on a hill start and literally had no power... And crawled up the hill at walking pace until the hill flattened out and I got going... I'll be rubbish on the Moffat run unless I sort this...
 
My vans back now, I've looked at the screw on the carburetor and it's quite a long way out. When I've got five minutes I'm going to screw it one turn.
 
I had exactly the same thing with Bonnie, a simple tweak sorted it out. But first there are a couple of checks you can do before taking things apart.
Your carb should look something like this. The linkages may be on the other side but it's basically the same.



First thing to check is if there is any oil in the dash pot.
Unscrew the black plastic plug at the top and withdraw the piston



Top up the dashpot with engine oil to the top of the inner tube you can see looking down



It will only take a couple of teaspoons full so don't go mad.

Next take the air filter off and lift the piston with your finger, it should move with a bit of resistance then drop right down with a little clunk as it hits the bottom.
You can see the piston in this pic, it has a locating groove running the full length.



Try those things first and see what happens, if no good then we'll delve deeper:eek:
 
Could the choke have an impact on the tickover? I adjusted it a while ago, so hopefully when I've adjusted the carburettor screw it will improve. My van starts to cut out after I've filled up with petrol, I'm only putting a small amount of redex in. I'm trying to find five minutes to have a look at it.
 
I guess the choke could be stuck on but unlikely if it's been running OK, but worth a look.
It could be, as suggested before, that debris from the tank has got through to the carb. If adjusting the tick over doesn't work try pulling off the elbow that goes to the air filter, on top of the carb then start the engine, build the revs up and put your hand over the carb opening a few times. The suction will be very strong and if there is a blockage sometimes this shifts it.
 
One thing worth checking is that the fuel tank breather pipe isn't blocked. May not be the cause in this case, but if the fuel tank isn't venting properly the fuel pump will have difficulty pulling the fuel from the tank, especially if you have a good seal in your fuel cap. A blocked breather will eventually create a vacuum in the fuel tank as the fuel is pumped to the motor. When the vacuum in the tank equals the suction of the fuel pump the fuel will go nowhere. Had this happen once to my Mk1 Triumph 2.5PI when I hadn't driven it for a few weeks. A wasp had decided to pack the end of the fuel tank vent under the car with mud for a small nest. Took me ages to figure out the problem.
 
If it starts conking out again take the fuel cap off, if the breather is blocked there will be a partial vacuum in the tank and you will feel the resistance taking the cap off. Then try running the engine again without the cap on and see if it cures the problem.
 
Beat me to it Panky! Not sure where the breather runs to as I haven't got to that end of my van yet. The vacuum created from a blocked fuel tank vent isn't that big as the fuel pump only works at around 4 PSI pressure. You could also fix a plastic freezer bag to the filler held in place with a tight rubber band. If the breather is blocked the bag will slowly get sucked into the filler pipe.

Another thing that have mentioned somewhere here before is that some old rubber fuel lines tend to shrink internally with age to the point where the motor will use more fuel than the fuel pump is capable of pulling down the fuel line. So have a look out for that too.
 
You've got to be quick;)
The breather goes into the filler pipe just below the cap, which is vented, so the actual vent flexible pipe would need to be kinked or blocked to pull a vacuum. It has happened though, I remember a particularly hot day on a beach when half of my fuel tank emptied through the cap because of the same problem:(
 
Thanks , so the plastic bag trick won't work, as it needs the tank to be externally vented.

In that case I'd check that the fuel cap is venting correctly.
 
I've turned the screw one turn on the carburettor, the van started fine but there's now quite a lot of petrol dripping from the carburettor which is a concern. I've turned the screw back to be safe. I also took the petrol cap off to make sure it's vented. Before I turned the screw the tickover was a little sluggish, but with it turned petrol starts leaking. Should I have the carburettor looked at?
 
It's leaking from underneath the carburettor, try and get a picture in a minute. It started fine, I then adjusted the screw and it started leaking. There is some petrol on top of the carburettor, and it does smell strong of petrol.
 
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