phbh idle problems

[leehuggy72]

Evening..

My delly 30mm phbh won't idle, i'm having to wind the screw right in just to get it to barely tickover..

i recently replaced the throttle cable,

when i set the throttle i wound out the idle screw out so the slide bottomed out then set the cable with around a 1mm play..
then i roughly set the idle and kicked her over..

it would only idle with the throttle, so i wound in the screw until i can't anymore..

could the spring be bound up..

the carbs only 200 miles old and have never had any issue before.

[nelson pk]

Sounds like an extremely rich or flooding issue. Two things to check initially.......look down the left hand side of the bell mouth of the carb and you will see the brass choke plunger. Make sure this is opening and shutting correctly by operating the choke lever. The plunger should completely block the hole off.
Second thing.....make sure the float valve isn't sticking and shuts off properly. If it was fine before and you haven't adjusted any jetting, I would check those first..
Only other thing is if the old throttle cable was tight and pulling the slide up slightly allowing it to tick over and now you've put a throttle cable in that isn't pulling on the slide it maybe showing up a rich setting. I would check the first two though. Choke is the most common issue.

[Rich_T]

Good advice above: One other thing with those chokes. The choke is sealed by a rubber pad at the bottom of the float rises. It is important that the choke cable has a fraction of float to ensure that the pad is seated on top of the fuel feed.

I had a customer visit once who had fitted a carb I supplied and wasn't happy as it didn't idel and was very boggy. It transpired his previous carb was a PHBH and the previous "fitter" had cut the choke plunger in half so that there was no slack in the cable. For time saving, when he fitted the new PHBL he simply swapped over the choke mech (as it is identical) and unwittingly transferred the problem with it. Looking down the choke hole (as I did initially) did not pick this up.

[leehuggy72]

Evening

had a look at the carb again today...

float is fine.. valve is fine.. choke is seating ok..

nothing else has been touched to the carb so its annoying me...

slide opens up and snaps shut and seats fine when throttle is used..

so i'm bemused..

the idle screw seems to work fine, i can see it work on the slide and start moving it up..

so why isnt the carb idling higher as i turn the idle screw..?

done the necessary checks i.e... air leaks, tightened everything up connected to this issue, cleaned carb...

has this happened to anyone else...?

[nelson pk]

Did the problem start as soon as you fitted the new throttle cable?

[leehuggy72]

i would say yes mate...but it looks and acts just like the previous setup....

[leehuggy72]

Think i'm going to take the carb off and give it a once over...

can't do any harm i guess

[goldeneye]

just had a lammy in with this problem, it was the slide worn on the wedge bit that the tickover screw puts pressure on. PHBH carbs have the screw on either side, dependent on model of carb. i had a carb with a left hand t/o screw, the lads scooter had a r/h- t/o screw. i swopped the slides (both the same) and fettled the tickover, problem solved. his slide works perfectly on the carb i have.