Thread: Chainsaw Problem

Originally Posted by rangieman

There,s the bait ,
Im ducking for cover

now now Judy dont be like that Punch should be here soon

Here and present

I'd be inclined to change the diaphram in the walbro carbi.

With fuel sitting in it (more common if you use premium) it can harden the diaphram which makes them hard to start and easy to flood.

You mixture should be no richer than 40:1....this isnt a motor bike and the cylinder is tiny in comparison and doesnt need as much oil for lubrication as a larger bore and heavilly loade 2 stroke bike motor.

If the carbi diaphram is stuffed you will notice that when you adjust the mixtures you wont get a lot of fine adjustment, thats a sure sign you need to spend the $5 or so on a diaphram and fit it and re balance the carbi.

The correct meathod for starting just about any 2 stroke is as follows :

1. Fill with fresh fuel (or top up with fresh fuel) and shake well.
2. Turn choke to full on and lock the throttle lock on
3. give 3 ONLY good pulls in quick succession (may kick during this stage, if it does kick go to next step)
4. Turn choke to half and throttle lock should disenguage
5. Give another 3 only pulls in quick succession (should start during this stage)
6. If it hasnt started or tried to start then turn choke completely off and hold throttle full on and give 3 pulls or so to clear the cylinder and flush with air.
7. go back to step 2 and try again

I think everything else has been mentioned

Nothing wrong with Shindaiwa stuff, I recon it is as good if not better than some of the brands out there which are quite popular.

As far as the Catalysts on the Husky's, you mix cant be any richer than 50:1 or else it will block the catalyst I believe.

I havnt had anything to do with them yet but there is a lot of chatter about them on a couple of other (industry) forums.

Originally Posted by mcrover

As far as the Catalysts on the Husky's, you mix cant be any richer than 50:1 or else it will block the catalyst I believe.

You believe, I confirm. The voice of hamfisted mixing!

But they run so clean, well worth it. Amazingly smooth for a two stroke.



Christ do they rev!!!

Originally Posted by B92 8NW

You believe, I confirm. The voice of hamfisted mixing!

But they run so clean, well worth it. Amazingly smooth for a two stroke.



Christ do they rev!!!

You want to try the new Stihl 4mix saws, they have heaps of guts and they are a lot quieter than the straight 2 strokes.

I tried one about a month ago with a 24" bar cutting stumps and it seemed to work about half as hard as the MS350 was although thats a small saw with a 24" bar on it anyway.

Yeah I said I believe because I havnt had any dealings with them hands on so to speak, just second hand info.

Most of the folks that have got them on the other forums recon it just requires getting used to not being heavy handed with the oil and to use the right oil and fuel and they work great.

Just to be different...
Is the spark plug giving off a nice fat spark??
All the symptoms are there for a piddly spark that works ok at high revs but oils up easily, then difficult to start next time.
I've got a Husky CDI sitting on my workbench coz mine was using plugs up. I'd buy a new plug and it was OK for a while then all the symptoms you describe. It could'nt be the mix as I was running the mower and a similar husky on the same fuel.
When I compared the spark between the two Huskies it was obviously insufficient spark, not the flywheel clearance or flywheel magnetism, hence the new CDI.
Its job number 32 on the list

Mate ...

A while back I had a 2 stroke mower that was a mongrel to start.

Herself bought me a can of "Start Ya Bastard" from Repco. Just aerostart under a different brand, but crikey ... did it work.

I reckon it'd fire up a corpse.

Wouldn't recommend it for anything you value ... but by the sound of it ... in this case ... why not give it a go ...

Where are your carby settings now ?
ie. how many turns out are the low and high speed needles ?
Where does the book suggest they should be as a starting point ?

Too lean on the low speed can make it stumble and falter under full throttle acceleration from idle until the high speed circuit kicks in.
In karts years ago we used to keep opening the low speed needle coming off a corner until the stumble disapeared.

Don't go changing mix ratios without re-tuning the saw either. Mixing a richer fuel/oil ratio, while giving the saw an extra slug of oil can actually lean it out unless the low and high jets are opened to compensate.
This is because you are displacing fuel with oil in the mix. In an extreme case it can result in a lean seizure, and all you've done is mix a richer fuel/oil mix.

Originally Posted by Redback

Now i'm no expert, but i thought that a 2 stroke would take a variety of mixtures from 20.1 to 40.1 with no probs, but bloody thing seems it need a specific mixture or it fouls the plug and won't start.

I agree. It is only 6 months old. It should be able to tolerate slight variations in the mix and still run. You are not inexperienced with 2-strokes and you know there is a problem with the saw. The problem you have is convincing the supplier that it is faulty.

If there is no pattern to the fault then I suspect that it is an intermittent ignition system problem. These are often the most difficult to sort out.

Why not leave the saw with them for a week and get them to start it once a day. Surely the fault will appear in that time.

FWIW I have a Shindaiwa brush cutter that has given no trouble at all. I never drain the fuel and have never changed the plug - I haven't even check the air filter. It is always surprisingly easy to start - let it kick on full choke, then one pull on no choke. I haven't met a 2-stroke yet that won't start using this technique.