268 update

[miker]

Right , checked flywheel key, all good there,checked for needle leak,all good there, leave the saw over night and there is fuel everywhere,took diapragm off and it seemed to be stuck down,thus keeping needle open?this is a new carb kit,could it be faulty?

[spudulike]

Right , checked flywheel key, all good there,checked for needle leak,all good there, leave the saw over night and there is fuel everywhere,took diapragm off and it seemed to be stuck down,thus keeping needle open?this is a new carb kit,could it be faulty?

 

Hell thunder - sell the parts, the damn thing is a door stop:biggrin:

 

The diaphragm should never push against the needle metering lever holding it open, what should happen is the top of the carb uses crank pressure to pull fuel up from the tank, the fuel goes through an internal gauze filter, past the needle and fill the lower metering chamber, once the chamber is full of fuel, the diaphragm is pulled away from the metering lever and the fuel stops flowing in to the carb as the needle closes.

 

One thought - dry the saw out, screw the H screw fully in and try to start it - don't scream it if it starts for obvious reasons but just interested if it cuts down the problem. I am thinking faulty main jet (should have a one way flow) or a deformed diaphragm.

[miker]

ill try that.

cant understand how i only pulled saw over 4-6 times ,put it back on the bench and when i went to the saw today the carb was half full of petrol,literally covered half the choke flap

[miker]

ive got a spare tank/handle,gonna swap that over,seems maybe its pressurized

[spudulike]

Possible the tank presure is pushing petrol in to the carb and a faulty main jet is allowing the fuel in to the carb - normally this is caused by a leaking needle valve - you sure it is working ok:confused1:

[miker]

did what you said, put a tube on fuel inlet and blew,activated lever and pressure released, sucked and held it my tongue,all good there, new carb i think!!

[spudulike]

did what you said, put a tube on fuel inlet and blew,activated lever and pressure released, sucked and held it my tongue,all good there, new carb i think!!

 

May be worth cleaning it with carb cleaner down the H and L screw adjuster holes before junkig it:confused1:

[geoff]

How about that & ultrasonic clean?

[miker]

got to go into the shop today for some parts so ill get them to ultra sonic it for me , update soon!!

[spudulike]

got to go into the shop today for some parts so ill get them to ultra sonic it for me , update soon!!

 

 

Yes - hopefully it will get it going - just purchased one myself and yet to use it!

 

The symptoms reflect a leaking needle valve with the only other possibillity being a main jet that has a faulty one way valve. Hopefully the US cleaner will sort it otherwise it will be a £25 EBAY special.