Husky 550xp mk2 issue

[jameshs22]

Hi Guys,

I have a 550 that isn't running as it should. It starts, idles and cuts fine with plenty of power but occasionally revs up after cutting even when the trigger isn't pressed. The only thing I can compare is to is when a saw is about to run out of fuel and the revs increase. If the trigger is pressed the revs will then return to normal idle speed.

 

Anyone got any ideas of what it could be? I thought the throttle cable may be getting stuck but I had a look and all seems fine 

[kram]

Opening the throttle, will move the accelerator pump if it has one, could be that the oring seal has started to fail and letting air in, until the throttle moves it. That is a massive guess. My only experience with the problem is a newish husq carb that wouldnt purge or start as a result. At first it was intermittent, sometimes purging and starting fine. I cant see any reason why mine would have failed unless they are using substandard orings on this part, but then I'd expect it to be far more common.

 

 

[spudulike]

Sounds like the throttle mechanism is sticking open a bit. 

Easy to see, pop the top cover off, look at the mechanism on the right side of the carb (closest to the clutch side), open and close the throttle, open the throttle and close it very slowly and see if it closes fully immediately.

You can start the machine and do the same then close the actual carb mechanism with your finger and if it works fine if you push it shut, check/lubricate the cable and mechanism plus clean the airbox area.

It is possible it has an air leak in the seals or around the cylinder front transfer ports but the autotune masks these pretty well. Plugging it in to the factory software can show if this is the case but check the throttle first, especially if someone has stripped it recently.

 

[jameshs22]

Thanks guys, I'll have another look at cable mechanism, if not I'll take it to the shop so they can plug it in