Stihl Hedgetrimmer a PIG to start

[chrisj]

Hi, my Stihl Hedgetrimmer is a nightmare to start. It is a few years old but it really is becoming a pain, and it shuold have loads of life left in it.

It used to be absolutely golden. Set it to start, put the choke on and prime it and it would fire on the first (or maybe second) pull. Take the choke off and it would start straight up on half throttle, blip the trottle and ready to work. Then stupid me. I though I've had it a couple of years and only ever put fuel in and used it, maybe it would be worth getting it serviced to look after it. It's never been the same since.

It came back and was a pig to start. Took it back and it came back no better. Reset the carb screws to factory settings and it was better, (although still not as good as originally) so I figured lesson learnt and have never taken any machinery there again. Years on and it's gotten worse to the point that it is now a complete pig. Doesn't matter what I try it can take 30 pulls to fire. Then when it finally starts it revs poorly and if you touch the trottle the revs die and it cuts out. Once it's properly running it's ok while you are cutting with it, but if you put it down, it either cuts out while on the floor or when you pick it up. Then to restart it you need to put the half throttle on.

Any ideas anyone?

[Hodge]

Is it a four mix? If so I think you have to have the valve clearance set up every so often. Mine turned into a pig to start and that was why.

[chrisj]

No it's a proper 2 stroke. I do have 4 mix machines though and intend to keep ontop of the valve clearances. So thanks for the warning.

[IVECOKID]

Which model is it and if it's a 45 then they can turn into a absolute pig to start .

 

Ste

[mikerecike]

Sounds like a carb tuning /fuel issue to me. After changing the spark plug and fuel filter I'd get somebody who knows how to tune a carb do it and get them to tell you what they are doing. If it dies just idling on the floor I tend to increase idle adjustment so I have half a chance at adjusting the carb.Then I'd find the low screw highest rev point. Then I'd rev machine and adjust high screw to max revs and then richen maybe an eighth of a turn.Finally I'd readjust idle to stop cutters moving but keep it ticking over. Then I'd test start and rev and then I'd test it from cold and adjust accordingly. That's IF it was a fuel / carb adjustment issue. These are the basics to give you half a chance and assuming you still have decent compression and a decent spark.

Edited April 19, 2015 by mikerecike

[spudulike]

I would pull the muffler and see if the exhaust port is blocked with carbon. It is a common issue on these small bore trimmers where they don't get run flat out all the time and the exhaust ports are very small.

 

It is not uncommon to lose half the port area with carbon giving poor running nad lack of power. I have got the piston so the skirt covers the port and eased out the carbon with a craft knife before and then brushed the debris out - go careful and it saves an hour or two stripping the unit down.

 

Other than that - shyte in the internal carb gauze strainer, hardened diaphragms, metering arm too low, carb kit fitted and gaskets replaced in incorrect order, choke not sealing properly, carb needs a US clean, fast idle setting not set/working correctly, low compression/scored piston, blocked tank breather, soft fuel line.

 

Think that lot is pretty comprehensive:thumbup:

[chrisj]

Wow. Lots of things to check. Thanks for the input everyone. I'll let you know when I've had chance to check it out.

[Treemover]

I had same issue, took of exhaust and threw it on bbq to burn off soot.

Ran spot on after

[Essexboy]

I feel that the carb just needs tuning.

[GardenKit]

Sounds like its just a little low on the LA (idle speed) and a little weak on the L screw for starters.

 

As it runs OK when its cutting I doubt its anything to do with blocked filters or carbon in the exhaust.