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ES2 carb still a problem!

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ES2 carb still a problem!

Posted by ben_tomlin at April 21. 2017

Paul Knapp and Robert Tuck kindly responded to my previous posts about my Amal 276 pre mono carb.  I thought the mixture was too lean on my newly (professionally) rebuilt carb because of spit back through the it and because it only runs well on full choke. I have checked the fuel level as suggested by Paul by making a small fitting and using a clear plastic tube and the level is just below the overflow hole in the float chamber cap and around 7/8" above the idle mixture screw (pilot air adjusting screw...is that the same thing?) when it should be 1/8" below it (as I understand it)....

Fuel also starts to drip out of the carb air intake after a minute or two before the engine is started so it would seem a weak mixture is/may not be the problem.....is the fuel level too high?.....any ideas please?

Cheers, Ben Tomlin

Re: ES2 carb still a problem!

Posted by David Cooper at April 21. 2017

Burlen told me the correct level is 1' 5/16" down from top of float chamber which comes to about 1/8 down from the top edge of the bottom cap of the carb body. That is with a horizontal carb.

My new carb  dripped to start with but it seems OK now. Dirt in fuel was preventing the float needle seating fully so the level rose slowly when the engine stopped. Maybe that's your problem?

Re: ES2 carb still a problem!

Posted by adam_davis at April 21. 2017

Sigh. Those carbs are often a problem with leaks due to the poor mechanical advantage of the float/float needle, unlike the monobloc which has a lever effect with its 'hinge' on the float. When your carb was reconditioned, did that include the float chamber? I doubt it. You could buy a NEW float chamber/float and needle as a last resort which wouldn't leak. A bit dear though, Surrey Cycles could supply. My brand new 276 from them has never leaked or flooded whereas a reconditioned one was so unreliable I swapped it for a monobloc.

Re: ES2 carb still a problem!

Posted by Paul Knapp at April 22. 2017

Hi Ben, if you were a bit closer, I would have a look for you. The level needs to be just below the idle mixture screw, otherwise it will leak out past the screw threads.

Remove the bowl and then carefully slide the float off the needle, which will then drop out. Put some coarse polishing compound 

(I use BRASSO paste) around the needle to seat contact area and  insert needle back in bowl, then lap the needle to seat by twisting and swivelling the needle around while gently pulling the needle up against the seat.

These carburettors do not leak if care is taken around all leak points. I have several machines with the 276/76 type units and only turn the petrol tap off when home in shed after a ride.

 

Be careful of dripping fuel, particularly when trying to start, as a back fire may cause a fire. Ensure you have the gauze screen (or air filter) attached to stop any unwanted flame.

Paul.

Re: ES2 carb still a problem!

Posted by robert_tuck at April 22. 2017

I had to fit an inline filter (nice vintage looking ally thing) before I could stop flooding.

Re: ES2 carb still a problem!

Posted by ben_tomlin at April 22. 2017

Thanks for the replies folks! It seems obvious then that there is a needle seating problem and I have already had the float chamber off and checked the needle which is obviously a nice shiny new replacement which I guess doesn't match the seating too well.  It may have been easier to lap the old one in which would have been a more precise match to its seating but I will have a go as Paul suggests. I may give the needle base a very light coat of aerosol paint first just to see what rubs off when I twist it around and this should tell me how well it seats before I do anything......I already have an inline filter and I'm seriously now thinking that I should have bought a new carb or at least a new float chamber as suggested by Adam.......and David, thanks for your reply on fuel levels as confirmed by Burlen.......

Re: ES2 carb still a problem!

Posted by ben_tomlin at April 23. 2017

Aaaaaargh!......needle now lapped in using the Paul Knapp method (brasso) and seems to seat well with carb no longer overflowing. Fuel level remains constant but is about 20mm above the pilot adjusting screw so way above the David Cooper/Burlen levels so surely the mixture cannot be weak?

However.......the bike starts easily and runs quite nicely but only on full choke.....open the choke up after the engine has warmed and it runs roughly and horribly spitting back through carb and backfiring.......not sure where to go from here...... It ran beautifully on the Indian Enfield carb but I don't want to go back to that!  Maybe a brand new carb is the answer!

 

Re: ES2 carb still a problem!

Posted by David Cooper at April 23. 2017

As I understand it, the level is supposed to be below the small overflow drain hole on the side of the carb just above the edge of the base flange.

No that I have much confidence in my own carb.  I've just lashed out about £300 on a new one and it's no better than the old one.  Bike is actually harder to start, and for some weird reason is not quite so lively on wider throttle openings - where the dodgy pilot circuit is irrelevant anyway.

Mine also dribbles a bit when on the stand.  I tested the level with some windscreen washer tube screwed into the plug hole on the side of the banjo below the main body, and the level went straight up to the 'correct' position (as I understand it) just below the overflow hole.  But then it slowly crept up higher, and fuel began to leak out  - probably I need to polish the float needle.  (if your is not dribbling then I suspect we are talking at cross purposes...and yours is probably OK now)

I don't think this happens on the road when fuel is being used, but I've no reliable means of telling.

I think a new clip-on 276 (jetted for 16H) will probably shortly appear on the members adverts here!  After I polish the needle+seat together.

Damaged a rib and can't test it again properly until I can get it on the stand painlessly...

Re: ES2 carb still a problem!

Posted by Paul Knapp at April 23. 2017

Ben, something not correct here, if your level is 20mm above the pilot air screw, this would make it around the middle of the intake bore, and fuel would be a gusher.

Why not take it back to the 'professional', the one who apparently didn't even lap in the new bowl needle to old seat.

As far as the large mixing body nut length goes, I just measured the nuts on three of my machines, and they varied from 1"to 7/8" to 3/4" long.

As previously said, ensure the tickler isn't hitting the float top.

Look up inside the float chamber lid at the small  central guide hole for the float needle, unsure there isn't any thing that catches or restricts the needle movement full travel upwards.

Re the choke, are you sure that you are moving the lever so as to pull out the cable, lifting the choke slide.

Is the bowl sitting vertical and not on a lean (not all bowls are the same)

...and David, your bowl needle needs the Brasso treatment, that's a classic sign you have!

Good luck fellas,

Paul

Re: ES2 carb still a problem!

Posted by ben_tomlin at April 24. 2017

Thanks folks....the saga goes on.......I turned the fuel on this morning and pretty quickly the carb flooded dripping everywhere including from the air intake.....looks as though the Brasso treatment worked yesterday but not today.  I jiggled the tickler thinking that it may have a bit of dirt in there but no good!  Tried to get hold of my 'professional' but no luck so far......and Paul, tried your tips in your last post but nothing has changed and the bike will still only run half decently on full choke, that is with the choke slide lowered (choke on).....as soon as I pull on the lever and raise the slide (choke off) it runs badly, spitting back through carb etc. Even when the carb doesn't flood the level looks far too high at 20mm above the air screw. Thought I'd talk to Burlen this morning about a new 276 carb and they have one in stock but reading David's post has me worried about that and I was thinking about fitting a monobloc but Burlen say that will have a flange rather than spigot fitting and the adaptors (spigot to flange) Burlen have the wrong centres and will not do the job...where to go now???

Re: ES2 carb still a problem!

Posted by David Cooper at April 24. 2017

My new 276 works OK - and certainly better than your description of your problems - I was probably just too unrealistic in my hopes.  I do intend to do as Paul suggests (thanks, Paul..), and lap in the needle better.  The bottom float chamber banjo is annoyingly inaccessible so I'm not keen.

I might change back to the old carb (when my rib gets better) since I'd rather have the bike perform better at higher revs on the open road than at low revs not far from tickover - but before I do that I'll change the plug on the principle that 90% of carb issues are (allegedly) caused by ignition - and vice versa.

 

Re: ES2 carb still a problem!

Posted by Paul Knapp at April 24. 2017

Ben, I am at a loss. I once had a blond hair come through the fuel line which was across the seat, causing the carburettor to slowly flood. I also have had the float needle foul in the guide in the bowl screw top. I have had a float with a pin hole causing it to partially sink. And the more obvious one, small bits of sediment OR the cork tap seal breaking up keeping the needle from seating properly.

AS for the other symptom, sounds like the main jet is partially blocked. All a mystery to me.

 

Re: ES2 carb still a problem!

Posted by ben_tomlin at April 26. 2017

Thanks Paul, at a loss like you......so had a long chat with Michael at Surrey Cycles and finally bit the bullet  by buying a 376 monobloc with spigot to flange adaptor (which Burlen couldn't supply despite having one listed under 276 parts).  Surrey Cycles were incredibly helpful and friendly and could have a supplied a new 276 (at the Burlen price) but hey, I've already got one of those (which is supposed to be now as new internally and still doesn't work!).......new 376 should arrive this morning...watch this space!

Re: ES2 carb still a problem!

Posted by Gordon Johnston at April 26. 2017

I have been through the whole list above with a 276 carb. The answer turned out to be a weak clip holding the float needle. The float was effectively free to slide up and down the needle. This resulted in occasional dribbles, occasional flooding and a refusal to rev above 3,000 rpm and it all got steadily worse.

Still, as a result, the bike got a top end overhaul and a magneto rebuild which as it turned out it didn't need. Sigh.

Re: ES2 carb still a problem!

Posted by ben_tomlin at April 27. 2017

Thanks Gordon, there was certainly no problem with my 276 float needle clip.........and my new 376 monobloc is now on the ES2 and Eureka.......no more flooding and no more carb spit back when I raise the choke slide!  It revs well and ticks over nicely now and I wish I hadn't wasted money on a 276 carb rebuild......I can certainly recommend talking to Michael at Surrey Cycles if anyone has a similar problem..........

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