OllyK

OK, so I've lost the instructions for the chainsaw and I have a blown down apple tree to deal with.

Anybody know if it's standard and if it's 50:1 or 25:1?

Matteeboy

Almost certainly 50 to 1 - same as our Stihl strimmer and most petrol garden machinery.

dan/scooby

iTrader: (2)

just buy a one shot bottle , put the whole thing to 5 ltr

al4x1

If you have any doubt go 25 :1, too much won't do as much harm as too little oil

OllyK

Mmm that's what I went with.

Think I may have knackered it. Put what I thought was 2 stroke in to find out later it was just unleaded. It turns over but won't fire. Possible spark plug issues I guess?

al4x1

did it run at all? if it didn't then you should be ok just drain the tank then get the spark plug out. 2 strokes are crap if you don't use them much so good luck, if all else fails a bit of easy start often does the job

tanyatriangles

iTrader: (2)

How old was the fuel you put in it? If it's old and has been stored in a vented container, it may have lost all it's higher octanes, so will be difficult/impossible to start with.
Try fresh fuel with 2-stroke oil in.

OllyK

It ran for a couple of minutes on unleaded and then spluttered and stopped. After a few failed attempts to get it going that's when I suspected the problem.

Yup, drained it all out, fresh can of unleaded and 2 stroke oil and a new batch made up. Turns over, so I've not siezed the engine. Just splutters on the edge of firing up but doesn't get going.

Matteeboy

Agree with Tanya - unleaded is terrible for going "off"
What make is it? I find anything made by Honda or Stihl takes any abuse and just keeps on going and going.

Assume you've fiddled with the choke settings? My strimmer needs half choke or it won't start.

OllyK

The mix is brand new, well a week old now.

It's a cheap and cheerful Gardenline. Used to start fine, full choke, 1 pull, choke in then another pull and away it would go.

Matteeboy

Olly - sorry I meant the pure unleaded you put in it - was that old? Not the same but I tried to start a super reliable Honda 2 stroke outboard with old unleaded and it would NOT start. New fuel and it was fine - but it took a lot of starting. From then on it was fine.

Might need to get it looked at!

Plucking Pheasants

As mentioned, 2 strokes require fuel to be in A1 condition to run right, the smaller the engine; the more tempermental they become if the fuel is mixed wrong or is old (if the fuel is six months, old stick it in the car with a full tank - not the Subaru though ).

No oil in the fuel mix will seize the engine if it was run, if it turns over and has good compression, you probably got away with it. Running with no oil in the mix or too oil much affects the air fuel ratio - and thus requires different mixture settings...no oil means the engine runs too rich, too much and its weak, both giving starting and running issues.

Third thing strokers need is perfect spark plugs. If its a bit old replace it. They are also fussy on plug gaps, so make sure they aren't too wide or it'll be a bugger to start when hot. Too narrow and it won't start at all.

Small 2 stokes should run on synthetic 2stroke oil, as found in the little "one shot" (which usually gives you the correct ratio) not the cheap mineral 1 litre bottles from BandQ (which is only really suitable for larger engines like mopeds and stuff) . A word of warning with the "one shot" bottles is some brand mix with 4 litres, where the average petrol can hold 5 litres.

Ratio should be about 1:50, but some manuafactures reccomend 1:40 or stronger if using mineral 2 stroke oil.

OllyK

Unleaded bought last weekend specifically for the job.

speedking

The chainsaw that I used at the weekend had the fuel : oil ratio moulded into the fuel filler cap.

Was 40:1.

May be worth scraping the sawdust off and having a close look? Or perhaps there is a label?

Matteeboy

Rather amazed at our 2 stroke boat engine two weeks ago - no use for 4 months and it's on a pontoon mooring so has had plenty of battering by the weather. Started first time with old fuel!

If my fuel gets to six months old in my (2 stroke) strimmer or (4 stroke) mower, I bin it.

Dave T-S

If a 2 stroke engine won't start after a period, it has a spark and the plug is ok but fuel was left in it last time, it is almost certain that the oil has separated out from the fuel mix in the carb and gummed the jets up, requiring a carb strip and clean.

When leaving a 2 stroke for any period always empty the fuel tank and then run it until the fuel in the carb has gone