Carb problem needing sorting!! :-)

[andyboy069]

Hi guys, me again. Ive recently bought a Honda Express Deluxe just to sell on but it has a running problem.
If you kick it over it wont start unless you hold your hand over the mouth of the carb, then it fires up, runs then cuts out but spits fuel out. It wont start again unless you put your hand over it, then will run and just stop again.
Its really bugging me! Also there is a black tube coming from the front of the carb apparently going to nowhere, if you blow throw it petrol comes out of one of the round holes just inside the carb opening (not sure what the hole is called) What is this tube for?
This has autochoke, i have supplied a picture of a black box on the side of the cylinder, is there a way of bypassing this as it clearly doesnt work!

many thanks


Note the wholes just inside that the fuel comes from:



Black box on side of cylinder:

[TerraRoot]

no idea about that autochoke, but a hand over the carb bell mouth makes it run rich (same principal as a choke) so i doubt the autochoke is working. the cutting out when you take you hand off the bell mouth indicates it's running lean, fix that by putting the airbox back on. or without the airbox just keep it going by not wholly covering carb mouth.

if you can make it stay going by holding the throttle open above a 1/4 then the pilot jet is blocked.

the extra pipe sounds like a vent for the bowl.

[andyboy069]

The extra pipe isn't a vent, definitely not. I also figured today that if I blow into it I can keep the engine running! Not sure why lol

[jawathemutt]

sounds to me the autochoke isnt working and the carb needs a strip and clean,the black tube equalises the pressure in the float bowl other wise you get a vacum and the venturi cant lift the fuel up the main jet,when you blow through the pipe you force fuel through the open equalisation circuit(air into the float bowl forces the fuel into the venturi)and keeps the engine running dont try this on the move

[andyboy069]

Ahhh that explains that then. many thanks! Any ideas what's causing it though? I've taken it apart, cleaned everything, blown through all jets and orifices (ooo er)

[dungbug]

Dodgy autochoke (?) How does it operate (electric?)

[andyboy069]

Surely the autochoke wouldn't cause it to stop dead...I thought it would run lumpy or rough etc?
And yeah its electric.

[TerraRoot]

no autochoke results in a lean starting mixture. no airbox/filter, also a lean mixture but all the time. not enough fuel, no starty.
the smaller the engine the more sensitive it is to small changes in jetting.