oilman wrote:Been working on it for many hours.
Breakerpionts,ignition and carb settings looks good.
There is still occational backfire.
By putting a drop of water on the throttleshafts where they enters the carbbody,I can see the drop get sucked in.By spraying startinggas at the same areas,there is an increase in rpm.
Using Carbtune II to sync the carburettors,I find that I have no indicated vacuum at idle.I have to increase the revs a liitle to get a vacuum.
Have anybody tried using dental floss around the throttleshafts as a packing or sealer?
Other suggestions?
I'm made this a seperate thread as not to mix
it with the points/ignition questions/answers
naaaa, haven't tried the dental floss.
IF one completely strips the carbs and remove the
throttle shaft
you'll find these throttle-shaft felt/fiber 'seals' in the carb body:
now IF you have a leak as you describe
it could be that you shaft-"hole"
is so worn out that air leaks in
or it could be (I'm just speculating) that
the little felt-"gasket"-ring
has either gone missing or has been destroyed
by immensing the carbs is heavy chemical carb'cleaner'.
(Randakk mentiones that possibility here: Carb rebuild (#12)
"....12. Improper cleaning methods. I stongly recommend against ANY immersion-type cleaning except this. If you "dunk" your carbs in a carb cleaner bath, you risk damaging a large number of felts which lubricate and seal the throttle and choke butterfly shafts. These felts are difficult to replace and there is no source for replacements..."
My take is that it could be the source of a leak as air would enter through
this holes and between shaft and bore/hole):
The problem with this level of disassembly is
that in order to get to all the felt-seals
one needs to remove the shafts
and in order to remove the shafts one needs to remove the butterfly's
and
..the screws that holds the butterfly to the shaft
is of a very special type.
They can only be used once!!!
It's very hard to see on the photo
but the screw is hollow at the end,and has a very small slit,
that has been punched after assembly to create an outwards tension.
This will see to it, that it can not move out again.
(You REALLY don't want screws sucked out of the carbs
and into the cylinders ...!)
and the other things, (IF you remove butterflys/shafts)
is that you REALLY need to know
how to set this up during assembly
in order to get the butterfly's into proper position
so the fit into the carb-bore is absolutely perfect.
Reminds me:
part of a carb "service" would be to try and get some lubricant
in there, to the felt and the shaft/shaft-bore.
It can be reached from the outside
and from inside the carb with some penetrating oil.
