dt4 idle and pick up

[pjb123]

this i think is a carb specific question
stripped and cleaned carb with airline
checked theres enough fuel to carb ==masses of fuel from gravity and pump
compression check 115 psi
starts real easy and will rev up with jiggling choke and throttle
but wants to die all the time on low revs
like a jet is bloked so blasted compressed air in every hole i could see with float bowl off
no difference

played with idle mixture screw all the way in and out== no difference
played with float height ==no difference
i cannot see any kind of idle jet to clean in float bowl
cleaned one on top
how does idle revs work on this ...

will run at higher revs without too much problem sometimes with a little choke on ..
it seems its all about weak mixture at low revs which obviously makes it lean also at high revs

the screw on side of float bowl seems to be a drain as openig it just lets fuel out

anyone undterstand this carb ====its got a pipe running through the middle of carb whats that for ..

even reduced gap in spark plug no difference
i am beggining to suspect crank seals ....
any ideas thanks in advance

i really cannot see an idle circuit in this carb just one main jet

[boats.net]

There maybe an air or fuel passage still clogged, you cannot always see with compressed air. try spraying fluid, like carb cleaner through all the passages.