[woodentop]

My 2 year old Robin strimmer is misbehaving. Its really hard to start and when it does go it races then slows in a constant cycle. The throttle seems to have little effect and it conks out. I have changed the park slug, fuel line and filters. It seems to be carb related  but I haven't taken it apart yet. Its a Walbro carb. Any ideas ? Thanx

Model NB2001 2 stroke

[Gwiz]

yes, it sounds like a petrol problem rather than electrics, or it could be a blocked exhaust.
if the fuel you are using is last years, then the fuel in the  tank may have been a bit "off", and some of this has gummed up the tiny tubes and holes in the carb. modern petrol goes off in a surprisingly short time, a mix of two stroke seems to go off even quicker. im sure that one of our chemistry boffins on the site will be able to tell you why.
back to the strimmer, i think if you take the carb off and take it apart/ clean and reassemble carefully, fill with brand spanking new two stroke it should go a lot better but BEFORE going down that road..............................., take the exhaust off and have a look at the exhaust port, just to make sure it isnt too coked up with soot, that can give similar symtoms to the ones you described.

[woodentop]

Thanks for the tips. I cleaned the port - nothing to clean really. I then stripped down the carb and cleaned it with carb cleaner - again no problems noticed. On starting it was a bit better but still not right. The racing has gone but it is still very hard to start , lacks full revs and conks out. I also replaced the ht lead and cap to no effect. I'm begginning to lose patience with the thing ! Any more suggestions as to what could be wrong ?

Thanks

[shaun]

what oil are you using in your fuel

[Gwiz]

well, it can only be a carb problem then. assuming that the carb is mounted onto a short manifold that is in turn mounted onto the side of the cylinder, and asuming that you have checked that the manifold is bolted on tight and the gasket is in good nick, it must be an air/fuel mixture problem. has anyone fiddled about with the mixture screws? does it have one or two adjustment screws? and if so, are they marked H and L?

[woodentop]

I'll have another look. I haven't touched any screws at all on the carb. It has fresh fuel and standard 2 stroke oil at 50:1. I'll try another brand - theres not much left anyway. Thanks for your patience !

[Gwiz]

not at all, think nothing of it.

[shaun]

have you tried these one shot 2 stroke oils,theres no faffing about measuring or guessing how much,1 bottle goes into 5ltr of petrol
do a search on e-bay for "2 stroke oil" most hire shops sell them

[woodentop]

Thanks for all the tips. I have ordered a new carb from Ebay in the U.S. It was only £15 inc shipping so its worth a go. Also got a gasket and diaphragm kit. If it doesn't work then I'll give in !

[shaun]

let us know wooden how it goes.i had the same problem and it was a choked exhaust that was on a partner.
£15 is a good price hope it works for yer