On a chainsaw one doesn't usually get much choice. The choke is usually either open or closed. Depending on the model this can either be a peg that is pulled to close the choke or a lever that is pushed down. In either case as soon as the throttle is touched the choke flips open.
Normal starting procedure is:
Push the bulb on the fuel line about five times to fill the float chamber on the carburettor. On modern chainsaws pumping more than five times doesn't hurt because the fuel lines are recirculating.
Close the choke.
Firm grip on the handle with the left hand (sadly necessary even for left handers, I've never seen a left hand chainsaw).
Grasp recoil starter handle, pull gently and take up the slack.
One long, smooth pull to start.
Allow to warm up for a few seconds before touching the throttle.
Ensure chain brake is off, both hans away from the blade, squeeze the throttle trigger gently and bring the engine up to speed.
Once this is done, starting again should be easy and won't need the choke.
Seems to be a favourite lie of those who maintain 2-T engines "proffessionally". I made the mistake of getting an outboard engine "professionally" service. It cost a fortune and the mechanic wibbled on about "clear jelly" blocking the carburettor. I reckon this was a lie because the engine was running fine before the service. I've since done all the (minimal) servicing myself and I've never had a problem with it or with the fuel deteriorating despite is being stored for six months of the year. The chain saw is used for two heavy sessions, spring and autumn. Other than that it sits in the barn and isn't subject to any particular regime between uses. Starts first time every time.
One of the bruscutters OTOH is a complete bastard to start.
Starting spray is not going to cure the problem.. even if it does gets a wizz out of it..
Things to note are the oil mixture,, old timers might not be aware of the advances in oil technology.. But the new low carbon mixtures of today are about fifty to one as opposed to twenty five to one with your ol Castrol..
Ok I spect most of you know that,, I have a Johnsered strimmer and a great big old Johnsered chain saw.. Oh wow,, Ive had some good fun playing with that beastie down the shore,,,
And a very hard learning curve on how to sharpen chains an look after this second hand machine that had been abused and neglected..
I got a right sore shoulder and ended up near enough in a state of collapse trying to start the big ghet..
One good trick was warming the plug with the blowlamp.. But it was only a short term solve..
Thing is to decide if your machine is sound,, and if second hand assume the numpties have been playing with it,, or neglecting it..Both most likely.. Make sure the filter is clean or even chuck it out temporarily,, it will make a slight difference when you put it back.. If the machine is sound,, first check your mixture.. Chuck out the old and get new,, I measure mine with a vetrinary syringe,, but partner do pre-measured doses in sachets,,,per five litre..
There will most likely be two adjustables screws on the carb,, one is the tickover mixture and the other is full blast rip roaring, mixture..
Gotta sort out which is which first,, also find the butterfly tickover speed screw,, Increase the tickover slightly and turn the others down.. Find which is tickover mixture screw for certain.. If you have difficulty turn them all down and slowly bring them up again..
I find my machines run nicely,, an its all about learning how to tune the carb,, if the machine is good,, Too rich a tickover chokes and floods the the engine,, better it is slighly weak,,,start to learn about hunting,, learn to listen to it..
Its all trial and error really but you got to understand that litlle carbby first and and experiment..
And listen to it,, when you do get it kickin...
I start on full choke,, till i get the first kick and then go to half choke,, at which point it usually starts..
And then I very quickly go to normal mixture and let it warm up a little while if it is running nicely.. Before i open the throttle..
They most definately are tempramental little beasties,, but they do respond to intelligent persuasion.. and add some considerable satisfaction to your strimming/ chainsawing duties when they are running sweat cos you tickled their fancy,, jus right...
Starting spray is not going to cure the problem.. even if it does gets a wizz out of it..
Things to note are the oil mixture,, old timers might not be aware of the advances in oil technology.. But the new low carbon mixtures of today are about fifty to one as opposed to twenty five to one with your ol Castrol..
I have two, two stroke machines. For one the handbook says 50/1 the other
Oh Well,, a bit of careless posting on my part.. I always get my oil at a certain machine factor where they sell the low carbon 50/1 mixture .. (as I think of it) I thought the whole point was in not gassing yourself in clouds of fumes while you work.. I must have taken it for granted that all small handheld two strokes were useing 50/1 now..
It might well be a fairy tail about petrol going off,, certainly I have never come across it either.. Though i do think it is a good policy to chuck out the old and replace with new when you are having starting difficulties.. As muck in the fuel and carb might be one of your problems... Or.. If the machine has been on site,, they often don't have time to look after them properly,, or maybe a rough ol woodman had it before you,, or the tank just got rusty on the inside with sitting unused..
If you have had the machine from new then you will know the score..
I will note more carefully what 25 to one mixes are available next time... Is it used in the filling stations for motorcycles,, ??
Yea OK,, Steve mentioned the volatiles evaporating.. And well,, Ill accept that it does,, Its just that i never had problems i Identified as bad petrol.. I might not know much about modern m/cycles,, but i have played around with with a few little engines in my time..
I had a Tiger Cub once,, when I was a boy,, and endless starting problems and knacking up of the big ends... Years later I learned my mother had been emptying water from my wellies into the oil and petrol tanks on the bike.. You gotta think of everything when you have starting problems.. Is what i learned,, but i never figured on that one..
had a Dolmar chain saw during the coal strike,,, Thats going back a bit,, I seem to rememder rich blue clouds of smoke too.. an getting shots of two stroke in the gas..
The guy in the link likes his machine though,, even if he does describe it a second world war tank..
The thing about petrol going off is not like milk. milk is OK one day off the next. Petrol deteriorates in time and eventually it is no good. I had a bike that had stood for 18 months and the petrol would not run the bike. It was a 600cc four stroke. I had to replace the petrol and nothing else and it fired up and ran sweet as a nut.
Same bike has since stood for 9 months and despite the petrol leaking from the filler cap in the sun the bike was happy to fire and run on the stale petrol. I would think that the performance would not have been as good as with fresh but it did start and run OK.
exactly. Petrol is a mixture of stuff and the more volatile fractions evaporate faster than the less. The less volatile are not capable of ignition with a spark in quite the same way.
Just thought to ask,,, if petrol is stored properly in an airtight jerry can,, how do the volatiles escape,, where could they go,,? Would it not then keep indefinately if it was stored properly in a sealed container in a cool place...
And M/Cycle tanks will have a breather i expect,,, So,, a half full tank with spansion and contraction allows scope for volatile passage/escape... Designed to serve the engine but not for long term fuel storage.. If you had a m/cycle off the road for a long time with a full tank,, would that petrol not keep longerr than one with a half full tank.....
Sometimes when your cooking an get all that nice smell,, but where does the flavour go,, please do tell,,,
I was just watching a documentary about that guy who went to the South Pole and died on his way back,,, his supply post had let him down.. Most importantly,, the parrafin,, caches were turning up half empty,,, They were only thirty miles short of salvation when they were beaten.. Someone suggested that if all the fuel had been in the tins they would have made it home.. They concuded that the extreme cold had shrunk the leather seal, and allowed the parrafin or petrol to escape/evaporate... ? I cant see them carelessly leaving the cans on their sides ...
Don't now why that came to mind,, a fuel storage,, story.. Hmm,,
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