Saving Old Seagulls

I have returned to the Seagull flock after a brief affair with a H*nd* !!
I have bought a Forty plus in very good condition and it runs a treat up to about 2/3 throttle - beyond that it just dies like its too lean. Is that normal?? Its not that I want to run it at full bore but the point is that it SHOULD! Any ideas????

Just ideas and in no particular order.

• Jet needs cleaning

• mixture needs adjusting

• Incorrect fuel oil ratio for needle fitted

• fuel level low in carb

• fuel flow from tank restricted

• tank vent not open properly

• points need cleaning adjusting

• weak spring on points

• plug

Thanks for that.
I can rule out all of those except adjust the mixture and weak spring on points - havent checked the points spring but feel its a carb issue. If I pat the intake (remembered from my Kart racing days) it runs fine.

How do I adjust the mixture???

There is a screw on top of the carb slide that looks like it may raise and lower the needle - is that it?? How sensitive is it 1/16 of a turn or a couple of turns??

Many thanks.

Villiers carburettor jet cleaning

I recently had a problem with a newly acquired 40+. The engine showed good compression and started first pull, but would not run without full choke. I first checked the main jet which appeared clear and would allow compressed air to pass. I checked for fuel line and tank filter blockages and for crankcase leaks to no avail. I then compared the main jet to another of the same type (Villiers M7J). The comparison model would allow a 22G (approx .026") soft copper wire to pass easily. The one that I was checking would not. I therefore took a length of the above wire, anchored one end around a round bar to ensure that there was no chance of it breaking at that point, and pulled steadily on the wire until it broke. Obviously, there was a substantial reduction in diameter at the broken end. I then carefully pushed this wire back through the jet. Copper being softer than brass, there would be no damage to the jet. I slowly rotated and pushed the wire until it was far enough through for me to grip the end with pliers and the pulled through until the full diameter of the wire was accepted. I reassembled the carbie, fitted it to the engine and ran it without further problems.

I know that the engine had not been run for some ten years and suspect that old fuel had formed a varnish coating on the inside of the jet without fully closing it. I know that other people have had this problem and trust that this will assist them. Be careful to treat the jet with care and do not force anything, as these jets are unobtainable.
_________________
David

Billy,
If its a Villiers carb then the mixture is adjusted by the screw in the top of the piston that you can remove by undoing the knurled ring on the very top. Normally it is flush with the top of of the piston but can be screwed down a bit if necessary. Screwing down weakens the mixture. If you fully unscrew it you can remove the needle and you will find it marked either 3 for 10:1 or 2 (possibly 2½) for 25 :1.

The screw you refer to on the side is I think the screw that retains the jet in the body**. Remove it and the bowl and you can lift the jet out. Clean it with carb cleaner and a soft copper wire. Note that the retaining screw locates in the slot not the round hole. Take care with both the bowl and the jet removed as the fuel control needle can then fall out. It goes back in pointed end first.

** Or did you mean the adjustment on the cable end , which merely adjusts the tick over speed

You'll find exploded diagrams of all the carb types on the main website in the FAQ section.

If it is not a Villiers carb then someone else will have to help.

Regarding the points spring it was just a thought and a remote posibility. If it is not firmly trying to close the points bend it a bit so that it does.

Thanks very much - the screw I was referring to was the one in the top of the piston - I have unscrewed it 1/2 turn and its very much better but it is now proud of the top of the piston.

I am going to check the jet isnt varnished up before trying another half turn out.

Many thanks to all for your assistance.

I have ordered a Workshop manual from John to help demistify things!

the screw I was referring to was the one in the top of the piston

Apologies for misreading your post. I realised much later that I probably had (I read slide as side )

If you have to unscrew the setting above flush then definitely the next thing to look at is the jet, but also make sure it is fitted correctly.

My 40 Featherweight, which has been converted to 25:1 with a no 2 needle, runs best with it down about 2¼ turns down below flush!

No problem and many thanks for your help.

The needle is a No.3 - would that cause the mixture to be OK at low revs but way too lean at the top end??
Cant seem to find much info on carb needles for the Villiers.
I am running on 10 - 1 at the moment.

Thanks in advance.

The needle is a No.3 - would that cause the mixture to be OK at low revs but way too lean at the top end??
Cant seem to find much info on carb needles for the Villiers.
I am running on 10 - 1 at the moment.

No 3 is the correct needle for 10:1 mix. It should run properly at all throttle settings.

All you need to know about the needles is in the FAQs on the main website. I believe you can reduce the oil to 16:1 while still retaining the no3 needle, but the air /fuel mix will have to be adjusted using the needle adjustment.

(I have a Villiers engine on a very old lawn mower that has more or less the the same carb with a 2½ needle. that uses 16:1.)

What oil are you using ? You should be using an outboard engine oil to a TC-W spec. Or a straight SAE 30 oil. You should not be using a multigrade oil. ( It wont half smoke on SAE 30, I used it for a while when I had access to a supply)

I am using Quicksilver TCW3 outboard oil - purely because I have loads of it lying about (I use it in my miniature gas turbines).

I am going to try richening the mixture to a point where its OK at full throttle then see what its like at tickover but I am guessing it will be too rich to run at tickover when the top end is right.

Oil Ok then! Is the carb fitted correctly, no air leak between it and the block?

Is the "Air intake compensator" fitted on the intake?

The seal between the carb and the block seems very good and there are no apparent airleaks round the knurled disc that holds the throttle slide in etc.

'Air intake compensator' ??? You got me on that one - if you mean the piece that looks like a big washer in the outermost end of the shallow air intake trumpet then yes it is fitted.

Will let you know what happens when I have a play.

'Air intake compensator' ??? You got me on that one

Thats what it is called. Dont expect it makes much difference but you never know. Item #18 in the diagram on john's website

Billy - you shouldnt try to run a 'Gull on 16:1 if it is earlier than a 1967 model I believe - covered in the FAQs.

I would try fresh 10:1 and get that needle flush with the seat as a starting point.