AMAL 376 Float Needle seat question.

[Josh Cox]

Have just rebuilt my AMAL 376/80 on my 1953 A10, not the original Carb, but am happy with it.

Fitted a new "Viton" tipped float needle and seat.

In the DRAGANFLY manual it states you should place a fibre washer under the float needle housing.

With this fibre washer under the float housing and the float lifted all the way up, it does not close the needle on the seat/housing.

Remove the fibre washer, lift the float all the way up and it closes the seat, i.e. no flow, which is how I believe it should work.

Any idea's ?.

With the fibre washer, the float would not be able to stop the flow of fuel, has anyone else experienced this ?.

[Triton Thrasher]

They didn't used to have a washer.

[beezalex]

Yes, the viton needles can sometimes change the float level, but you need to check that regardless.  And yes, a fiber was not originally placed under the needle seat, it will make the float level MUCH too high.

[groily]

They didn't used to be there, shouldn't be there and whenever I've found one there I've removed it. Shouldn't need it as the surfaces are flat. Really common source of grief as so many people put them in. Surprised that Draganfly recommend it with these needles - I have tipped ones in all bikes with Monoblocs, no fibre washers and no problems. Maybe Draganfly are selling replica needle housings with different dimensions or something that makes the washer necessary - weird.

[Josh Cox]

Thanks Groily,

Sounds about right, I purchased the parts form AMAL, just happened to read that in the DF manual, although the pictures on the AMAL website also show the fibre washer:
http://www.amalcarb.co.uk/carbDetail_monobloc.aspx?float=null&engine=null&bore=null&series=null&carbID=599&numberOnDiagram=39&partID=-1&CarId=

[groily]

You're right Josh, and I'm surprised. I've no idea why it's shown because it will raise the level horribly as Beezalex said or even fail to control it at all. Unless the replica parts available now are machined smaller in height and the washer has been allowed for, which would be easy enough to do. I've never had a leak there - leaks normally happen on top where the little fibre washer is necessary, or from the float chamber because the lids are always distorted through over-tightening. I have had to take up to 25 thou off old lids to get them true.

[flashblack]

Hello all,
            This thread has been interesting to me because when i bought my new monobloc for the A10, it came with the fibre washer and also i was told that`s how they are made now. So anyway, i tried it with no fibre washer and it just ran quite lean, so mine definitely likes it with the washer in place. Perhaps the plastic floats are slightly different from the old brass one`s where the float needle contacts it? that could compensate for the level change?
These new monobloc`s also come with a smaller section `o` ring and groove on the mounting flange, for some reason. Seems to me it`s a case of fixing something that wasn`t broke in the first place!
I`m sure there was a reason for it!

   all the best    Richie

[groily]

several possibilities there then! Hadn't thought of the plastic float thing, although I do have one somewhere but not on a bike. Could well be they affect things too. Typical if some parts need the washer and others don't - a solution looking for a problem. Weirder and weirder. Someone at Surrey Cycles or even at Burlen will know for sure. I shall stick with what I know works though - old bits and no washers - and only face this hurdle if I have to buy any newer parts!

[cus]

G'day All,
Just following on from that, I have the original old 376 on my bike that I re-kitted, part of which
was a new float. I purchased a new old stock amal float (looks like alloy), a wedge type shape.
So put it all together & flicked the petrol lever...fuel p___sed out of the tickler, so either the
needle is too short or wrong float. I noticed that the float does fowl on the screw tunnel in
the float chamber. So anyway, pulled out the old float, which is more drum shaped, & someone
has put a dent in the top, so it doesn't fowl on the screw tunnel, I gave it a dunk in a glass of
water ( no bubbles ) so put it in & no worries, but yet to have a road test, still waiting on
pipes, I think they shipped them on a row-boat,

Cus

[flashblack]

In the DRAGANFLY manual it states you should place a fibre washer under the float needle housing

Also, in the draganfly catalogue it says "When using a `viton` tipped needle, a fibre washer must be fitted under the needle housing".
Maybe the needles are longer? I don`t have an old one to compare with.
Anyway, this subject has got me now, and i want to check my float level with a temporary perspex float bowl lid, problem is, i can`t find the measurement anywhere!
      Anyone got any ideas?

                            Richie

[ebsbury]

When the Monobloc carb was re-introduced it had acquired the fibre washer under the float needle seat. They were not fitted to the earlier Monoblocs. The dimensions of the float needle seat are unchanged so the seat fits old and new Mnonblocs. If you are fitting a new needle and seat to an old Monobloc leave out the fibre washer, on the new Monoblocs include it.

On some bikes, especially with steep downdraughts which the Monobloc was never very good at, it can be a useful feature as it introduces the posibility of lowering the fuel level by reducing the height of the washer, previously only possible by filing down the float needle.

The fuel level on a Monobloc is within a 1/16" either way of the pip underneath the Amal logo on the float bowl cover. On the other side of the carburetter the mark is 3/8" below the centre of the jet block plug screw.

If you don't have a float bowl cover with a perspex cover, you can take the pilot jet cover nut off and fit a clear tube over the end of the pilot jet to see the fuel level. The other option is to glue or braze a tube into an old Main Jet cover nut.

[flashblack]

That`s excellent information, i will now make a cover from perspex and check the level.When i do, i`ll post a pic of the "experiment".
                              cheers  R

[flashblack]

Things to do when you`re bored!

So here`s a pic of my fuel level check, not perfect as the perspex was a bit too brittle and cracked, but it did the job. You can just see the small dot to mark where the pip on the lid is, the fuel level is exactly 1/16" above the dot, so right on the upper tolerance. I`m happy with that, though i could fit a thinner washer to lower it a bit if i felt the need to.





BTW ebsbury, by saying that the float needle and seating are unchanged, am i right in thinking that the carb body itself is the bit that`s changed on the new carbs, a slightly different casting perhaps?

  cheers, Richie

[Josh Cox]

FYI:

Dear Sir/Madam,

Original Amal monoblocs were not fitted with a washer under the seating, however new ones do have the washer fitted (the bodies are machined different to allow for the washer), this allows for some adjustment when fitted in a down draft position to lower the fuel height slightly which in some applications caused fuel to drip from the pilot mixture screw.

Kind Regards,

Customer Services
 
Burlen Fuel Systems Limited - The SU and AMAL Carburetter Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA
Tel: +44 (0)1722 412500   Fax: +44 (0)1722 334221   
 

[groily]

There we go then, well done Josh - the machining is different, good reason  given . . So it's 'old bits, no washer' . . .so everyone's right - and loads of words. Not sure about the tipped needle thing - will measure some. Have replaced all needles on various bikes with tipped ones over recent years without adding washers anywhere, and no problems, with old bits, to date - but haven't checked float heights properly. Funny how little things can cause so much angst!