[Ade]

Hi to anyone that can help with a fuel problem with my petrol strimmer. It idles ok & I can have it on fast idle with choke on but when I throttle it, it goes sluggish & wants to stall. If I let go of the throttle it returns to idle but if I persist with the throttle the engine just die's in me. The fuel mix is fresh & some who has already looked at it said the fuel jets are ok. Has anyone got any ideas......

[Steveharford]

If you've checked the jets then I guess you will have checked the air filter.?

[Ade]

Hi Steve thanks for replying. Not sure if my friend cleaned filter when checking the jets so I'll do that myself. Out of curiosity what will not cleaning it do? IF this isn't a cure what can I next check. Many thanks ade

[Steveharford]

Hi Ade. Bear inmind I'm no expert but if the fuel is good and the filter clean then maybe change the plug. Worth a try for what it costs. Cant offer any other advice im afraid.

[New shoot]

I've just moved this into here, so it gets seen by all the forum members who know about machinery and engines 

[Ade]

Hi Steve. I carry a spare plug so have given that a go but still no joy. Spoke to the site where I bought it from & they say they have had issues with the petrol filter so they are sending me a new one so fingers crossed that will remedy the problem. Cheers again for helpful suggestions. ade 

[Steveharford]

Ah great. A simple explanation, which is good. Sounds promising. Good luck

[Mr Mole]

Another couple of points......
Inside the fuel tank of my   Sthil strimmer   Is a flexible rubber pipe with a filter on the end.  This is the fuel pickup pipe....the idea is that no matter what angle you hold the machine this filter will always fall  to the lowest point to continue sucking the fuel up....if yours has this arrangement fish the pipe out and either clean or replace filter.

The other thing to check is the exhaust ......usually they have a spark arrester screen...this is a fine metal mesh that the exhaust gasses pass through so that any bits of red hot carbon gets caught....in time it gets clogged up and restricts and eventually stops the the gasses escaping ....
This can give similar symptoms to the one you are experiencing ...

If you google "strimmer exhaust spark arrester screen".  YouTube have several tutorials on cleaning them..

[jezza]

hi check the diaphragms in the carburettor one should have a metal or plastic  disc on it this is the motoring diaphragm ,hold it up to the light and check for a pin hole in one of the holes in the disc it will never run with a pin hole also check the needle valve under this diaphragm it could be seating wrong   jezza

[MalcW]

You mention that idles OK with choke on; what happens if you take the choke off? I've known similar symptoms when there's an air leak on the induction side, meaning the motor is running too lean.

[Mr Mole]

Be nice to know if the problem was sorted...if it was ..what was the cure

[MANOFSTHIL]

Hi depending on the type and make of strimmer you have, the fuel mixture adjustment may need setting/tuning on the carburettor. I had a similar problem with a generic strimmer some months ago, their are x2 screws located on the carburettor casing marked H & L in most cases, the H adjusts the running at high revs and the L adjusts at low revs, only attempt this if you have knowledge of machine etc... as once you start messing there no way back, only use very small turns to adjust whilst engine is running, if your unsure drop it in to your local repair shop they should be able to sort it out quickly and it won't cost the earth. Hope that helps 😎

[shedmeister]

Two questions for you. What fuel mix are you using and what color is the end of the plug when you take it out.
The plug should be a light brown color if the fuel mix is correct. if it is black and oily you are using too much oil in the mix.

[redsquirrel]

You mention that idles OK with choke on; what happens if you take the choke off? I've known similar symptoms when there's an air leak on the induction side, meaning the motor is running too lean.

2 strokes get this symptom when a crankseal fails. wouldnt have thought it would be an economical repair unless you can do it yourself