STHIL TS410 REVING ISSUE

[IAN IDG]

3 minutes ago, spudulike said:

That sounds like a sticky throttle as an air leak may cause the idle to be higher than usual, the engine to rev much to high on full throttle, perhaps a lag in pickup and holding on to revs rather than snapping straight down to idle when the throttle is closed.

If you rev the engine flat out and the revs stay flat out and trop very slowly than the first thing is to check the carb throttle assembly, carb throttle return springs etc are all clean and lubricated and make sure that when you release the throttle, the throttle valve (brass disk in carb nearest the engine) snaps completely shut.

You can start the thing with the top cover off and manually push the carb closed with the small plate the carb throttle rod fits to after revving to make sure the mechanism does work and if the saw drops back to idle as it should, your throttle is sticky.

If the engine still takes time to drop back to idle even with you pushing the throttle valve closed, it is most likely an air leak.

the carb is new but I will check it ,I will  also check the rubber gaitors they may be split

[adw]

Compression test!

[spudulike]

20 hours ago, adw said:

Compression test!

But that wouldn't cause it to over-rev, are you thinking it may have nipped/seized because of a possible air leak or is it a case of Chainsaw Techs Tourette's?......if it is..."GRUNION PINS"!!!!!

[adw]

I’ve see too many knackered power cutters and people changing carbs,filters, plugs and everything in between, before they have assessed the condition of the engine, as you know concrete dust mixed with fuel is lapping paste, then throw into the engine and what do you get, so he needs the confirm the internal are all good before we waste our time suggesting other things, back to work Monday so I am a bit pissy this morning.

[IAN IDG]

22 hours ago, adw said:

I’ve see too many knackered power cutters and people changing carbs,filters, plugs and everything in between, before they have assessed the condition of the engine, as you know concrete dust mixed with fuel is lapping paste, then throw into the engine and what do you get, so he needs the confirm the internal are all good before we waste our time suggesting other things, back to work Monday so I am a bit pissy this morning.

This isn't my first rodeo !! I deal with these cutters on a daily basis so I am well aware of the damage caused by dust .I checked the cylinder & piston , crank & seals they are fine , so sorry to waste your time, ps lucky to have job to go to on a Monday morning.