honda brushcutter running problem

[wagon]

Honda UMK435E brush cutter running so fast the cutting attachment is rotating constantly even in idle, idle screw adjusted with no effect, please can any one advise

 

[Burnerman]

Is there any slack between the throttle trigger and the carburettor, cable wise? Often the cable gets wrapped around the machine shaft - especially if it has the cow horn bars.
John

 

[wagon]

Thank you for replying Burnerman. Ive checked the cable which is working fine and is in the correct position.
Ive also emptied the petrol out, replaced with fresh, checked and cleaned the air filter and cleaned the carb the engine seems to run alittle slower but the cutting attachment is still rotating.

Any ideas welcome

 

[Burnerman]

Presumably the throttle lever is now clear of the backed off tickover screw, and manually trying to close the throttle has no effect?
In which case, so long as the choke lever is working (they do have the effect of raising the tickover speed a little) I would guess the problem would be an air leak into the carburettor or manifolds somewhere....check too that the screws holding the priming bulb plate are tight.
Its usually two strokes that suffer from this syndrome though......!
You are certain the tickover speed is too high, and not the centrifugal clutch rusted up? The brush cutter blade / line spool should be free to spin by hand.
John

 

[wagon]

Will check all above tomorrow and get back to you Burnerman Thank you

 

[wagon]

Sorry I did not get back sooner Burnerman, other 'things' have taken priority.
Stripped carb, checked all screws ect, engine now running very smoothly, sounds good, however the cutting attachment is still running in idle, any advise welcome.

 

[Burnerman]

From what you are saying, the motor is now able to run slowly and smoothly, but the cutter head still spins?
If so, the centrifugal clutch isn't releasing, due to rust on the spring pivots inside....the engine needs to be detached from the long drive shaft to get to the clutch.
John

 

[wagon]

Yes, the engine is now fine, I have WD40ed the bolt heads at the top of the shaft by the engine and hope to dismantle this weekend, will let you know what I find.

 

[wagon]

Detached the engine from shaft, within two calipers with central spring, plenty of carbon dust no rust, cup /drum at top of shaft held to shaft with four bolts unable to remove three bolts as they do not align with either of the insert / removal holes, cup /drum not tight on calipers on detaching, cup /drum could be turned freely which in turn turned the attachment head. Thoroughly cleaned dust out reassembled, head still spinning constantly. Any more advise very welcome.

 

[Burnerman]

Scratching whats left of the memory cell......4 phillips screws hold the grey plastic driveshaft cover to the engine. Removing these reveals 4 deep hexagon nuts that hold the clutch housing onto the motor (best to remove the engine cover here.....2 allen screws?
Undoing the hexagon nuts allows the clutch housing to come free, does it not?
Have you actually exposed the two clutch shoes?
John

 

[wagon]

I exposed what you have called the clutch housing to me it looked like the brake calipers you find in the braking system for clasic Volkswagons, that is why I discribed them as calipers, sorry for any confusion.