Mitox 25C

[richrich123]

Hi Everyone,

New to the forum and wondered if anyone could help with this issue.

Strimmer just has just failed to start last week. I noticed the fuel lines looked a bit worn so fitted new fuel lines and a new fuel filter. Still wont fire. Checked spark plug and its sparking fine but I had a spare so have replaced it anyway. Still wont start. I have just put a little fuel directly into the carb and again, wont start, fuel is just splattered out the exhaust.

As I have a spark and fuel in the carb, I'm out of ideas on why it wouldn't at least be firing initially. Before I succumb to the local shop and a 2 week wait to have it looked at, just wondering if anyone has any other ideas I could try/test/eliminate.

Many Thanks
Rich

[Mick]

Hi Rich, and welcome to TGMF.

If you have fuel spitting out of the exhaust it sounds like the engine is flooded and maybe has excess fuel sitting in the crankcase.  Is the plug getting wet when you try to start it. 

Probably not relevant, but make sure fuel is fresh, and not left over from last year, pump fuel has a pretty short storage life these days, in fact STIHL for example recommend 30 days.

If it's had old fuel sitting in it for a few months you'll probably need to get the carb cleaned, change diaphragms etc to go along with your already replaced fuel pipes. 

[richrich123]

Hi Mick,

Many thanks for the quick reply. I did empty all the fuel inc jerry can and replaced this week with fresh and mixed up a new litre of fresh fuel at 40:1 (and then replaced fuel lines, filter etc so fuel is good.

Spark plug doesn't appear wet but I did remove plug and pull starter for a while just to push anything extra out.

I had considered stripping and cleaning the carb and if that fails, a new new carb kit and rebuild it. With my limited knowledge, I just wondered if I wasn't getting any kind of fire with fresh fuel in the tank, new fuel lines, new fuel filter, new spark plug and lastly adding a little fuel directly into the carb, would cleaning / rebuilding make any difference it it isn't firing?.

I had always thought that if you have fuel in the carb and it wont fire (even initially) it has to be a plug/lead/ignition issue but that doesn't seem to be the case and the plug is sparking fine.

Sounds like I should strip and clean the carb as the next step then?

[Mick]

Obvious things like having enough compression and whether the spark is in the right place timing wise are also a consideration. Timing being out severely can also cause it not to fire, this happens on Stihl machines where the flywheel has slipped and sheared the moulded in key, but not so common on other brands I've seen so far.

Also make sure exhaust port and or silencer isn't blocked solid with carbon.