What cause the toilet to keep running after flush?,

[Zehroni]

it flush perfectly but some times keeps running
It is an ole fashion toilet not close couple, and the system is the one that is connected to a chain, could be the diaphragm has parished

 

[holty]

are you still sat on it? overflows out of what? what type syphon ? not the best info. but thinking flapper valve.
http://www.screwfix.com/p/fluidmaster-replacement-flapper/65664?_requestid=782862

 

[HERTS P&D]

Internal overflow with a faulty float valve.

New float valve/washer needed.

I'll get my coat.

Andy

 

[Zehroni]

The inside is similar the this one
http://www.diy.com/nav/fix/plumbing...3mm-Dual-Flush-Siphon-11477980?skuId=11988687

 

[holty]

http://www.discountedheating.co.uk/...two-part-syphon.html?language=en&currency=GBP

?

 

[Zehroni]

Holty, do i need to replace the whole thing or the plastic diaphragm inside

 

[texasholden]

You need to check what is happening whilst it's running.

Either:-

1) the cistern is full of water, but the inlet valve is not shutting off, in which case you should isolate, and clean the inlet valve internals (debris could be the issue)

2) the cistern is empty, not filling because the discharge valve (syphon unit) is failing to close properly. In which case you probably need to replace the seals at the base of the syphon. Have a look at them, and you might be able to sort them out without replacement (sometimes they get blisters/crud on them).