Misc: Carburettors LEAKING CARBURETOR

[Simon Dinsdale]

Your link deals with TT carbs. Question here is about 229 type, same goes for 274 Amals , I guess. Is there same brass plug with punch mark ? My thinking with these Amals was the fuel level has to be maybe max. 5 mm below air adjuster screw . So then that hole above the locating pin will be lower still - and drip.

Vic

Vic
Yes that hole you refer to is below the fuel level but that cavity the hole feeds into should not have fuel in it during normal running conditions. To get fuel leaking from there you either over flood the carb and so fuel flows over and through the pilot jet and down into the cavity /air feed area and out the hole Which is exactly what the hole is for. The other cause is the large gasket under the big nut that seals the bottom of the carb body to choke block is not sealing and letting fuel past or the needle jet is not seating correctly into the bottom of the choke block And letting fuel past.

I spent many hours studying where air should be and where fuel should be in these 89 Amal carbs and later 289 & 229 carbs.

 

[fogrider]

My B twin has been running way too rich, I had set the fuel levels at the oft quoted 1/8th below the pilot screw. ( what are the origins of that ?) Cutting a very long story short, I rang Burlen and asked for the correct, as designed, fuel level for a 276. A very helpful chap told me it should be 0.9" above the float arm. But, says I, there are different depth spigot nuts that the float arm is fastened to. OK, says he, it works out as 1/2 way up the top band of the spigot nut. That's when I spotted I had 2 different depth spigot nuts. After juggling nut depths etc etc, the level is now 0.9" above the float arm and is just above the middle of the top band of the spigot nut.
Whats' the mixture like now ? - don't know, the damn Boyer ignition has packed up. !!
Work in progress - will advise when I'm up and running again.
By the way, after drawing up an accurate section of the 276, 0.9" is 3/4" below the floor of the main bore. Both the Monoblock and Mk1 concentric have their fuel levels 3/4" below the bore too. mmmm
We shall see !
Regards all....

 

[greg brillus]

There are at least 4 different height base nuts for the 276 carb's that i know of and have had on the bench in front of me. Perhaps they suit other models in the early side bowl Amal carbs, so this is probably why so many versions exist.........A pain if your carbs are made up from bits and pieces. The 2 on my original Rapide were both wrong and the level was too low........Only after some homework did I find out why........Cheers.

 

[fogrider]

The guy at Burlen was very helpful - they only stock 2 depths ( long and short ) being 5/8" for the short and 15/16" for the long. One of mine was 1.1/8", the really deep one, which is apparently quite rare as only made for a few years yonks ago.
For the benefit of those trying to judge fuel level on the side of the float bowl, as I was doing, the obvious way, with the flexy sight tube, is to hold it against the spigot nut itself , a direct read of where the fuel is in the carb. Why did'nt I think of that before ? Doh.......
Regards all.