viliers carb problem

niander · Post by **niander** » Sun Aug 26, 2007 7:40 pm

I got this viliers carb problem
on this little LS
it ticks over fine but doesn't seem to want to run over half throttle
kind of 4 strokes but then the revs build up slowly and then will run clear
compression is good
btw what is that little screw for by the fuel inlet...should it be set so many turns out?
btw main jet is clear.

Hugz · Post by **Hugz** » Mon Aug 27, 2007 5:53 am

Hi, Little screw is the brass centrepiece (jet) positioner. There is a notch on the base of the brass gizzo which the screw goes into.

Hugz.

niander · Post by **niander** » Mon Aug 27, 2007 11:05 am

Ok i now know whats wrong with this! the fuel is to high in the carb so much it spits it out of the air intake ..effectively like running on choke all the time!
ok the brass plate that pushes the fuel needle is more or less flat...i think it needs bending down?
But how much?
when i turn off the fuel and once the level in the carb drops shes sweet as a nut!...this proves the problem.
it needs bending down?
But how much?

niander · Post by **niander** » Mon Aug 27, 2007 11:06 am

Hi, Little screw is the brass centrepiece (jet) positioner. There is a notch on the base of the brass gizzo which the screw goes into.

Yea i see that now thanx.

Vic · Post by **Vic** » Mon Aug 27, 2007 2:34 pm

it needs bending down?
But how much?

When the float is held up against the float lever the distance between the top of the float and the underside of the carburetter body should be 7/32"

Thats what mine measures and what an old Villiers motorcycle engine handbook says.

Measure close to the centrepiece(jet) using a set of drill bits

niander · Post by **niander** » Tue Aug 28, 2007 1:02 pm

ok i adjusted the brass float plate
it seems a bit better but still doesn't seem right it will accelerate only slowly building up speed
seems kind of choked up

could the plug cause this ?

is it normal to have a pool of petrol in the intake nozzle?

Hugz · Post by **Hugz** » Tue Aug 28, 2007 2:03 pm

Hi, your points might be too narrow. Try opening up the gap. If the gap is too small it retards the ignition/timing causing slow acceleration particularly at low speed. If not check the magneto base locating screw is located into the dimple. Sounds more electrical than fuel.

I assume that it is running 10 - 1 and hasn't been changed to 25 -1?

Hugo.

Vic · Post by **Vic** » Tue Aug 28, 2007 7:10 pm

I assume that it is running 10 - 1 and hasn't been changed to 25 -1?

Check the number stamped on the needle near the top (you have to take it out to do that) and compare with the info on the main website to determine if it has a 10:1 or a 25:1 needle fitted. The needle is correctly set? (BUT to get my Featherweight, which has been converted to 25:1, to run properly I have to screw the needle down about 2Â½ turns below flush with the top of the piston.

Are you sure that the float needle valve is shutting off properly and that the carb is not flooding all the time. Just let it stand for a while with the fuel turned on and you'll soon find the answer to that.

If you have not already done so check/clean/reset the points and also the plug. Renew the plug if in any doubt.

You are using a suitable oil in the fuel mix and you are using fresh petrol?

niander · Post by **niander** » Tue Aug 28, 2007 7:56 pm

The screw is very very tight above the needle
so i haven't been able to look I'm running 10 to 1
if the needle is 25 to 1 could that cause it?
the ignition is off a British silver seagull 102cc
any good?

Hugz · Post by **Hugz** » Tue Aug 28, 2007 10:51 pm

niander wrote:the ignition is off a British silver seagull 102cc
any good?

Ahaa... I wonder if who changed the magneto also changed the carby. Might be the wrong one.

Post by **charlesp** » Tue Aug 28, 2007 11:40 pm

Ignition from a Siver Century is fine to use. So is the Villiers Carburettor.

Vic · Post by **Vic** » Wed Aug 29, 2007 12:49 am

I'm running 10 to 1
if the needle is 25 to 1 could that cause it?

I think you'll find that running on 10:1 with a 25:1 needle will give the symptoms of running weak rather than running rich.

niander · Post by **niander** » Wed Aug 29, 2007 9:14 am

is it normal to have a pool of petrol in the intake nozzle?

Hugz · Post by **Hugz** » Wed Aug 29, 2007 10:27 am

Never seen that with any of mine.

Vic · Post by **Vic** » Wed Aug 29, 2007 7:40 pm

I'm not sure what you mean by the "intake nozzle". Do you mean trapped behind the air intake compensator?

I have never seen any pools of petrol anywhere. Is your jet correctly fitted with its washer and with the retaining screw in the slot, not the round hole.

See the diagram on the website

Is the needle valve closing properly and shutting off the fuel flow. Is the float ok, not holed and not half full of fuel.

Your engine is fairly old. Does it have a (metal) float chamber that does not have a couple of vent holes near the top? If so then when you press the flooding button as the fuel cannot flood out through those holes it floods out through the air intake. That can leave fuel in the intake at least untl the engine starts.

Saving Old Seagulls

viliers carb problem

viliers carb problem

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