Chainsaw Starts and dies within a half second

[Double-Eh]

Jonsered 2045 turbo. I can get it to "start" with a couple pulls, on choke. But before i can even get my hand off the recoil handle and onto the saw, it dies. Pull, pull, pull, pull, pull... Nothing. Doesn't matter if I choke or jot, throttle or not, even used quick start. If I come back 3 minutes later, **please refer to 'I can get it to "start" with...' **
I've done a carb kit, and a thorough clean and nothing changed. It has good fuel in it.
Plug looks okay, I haven't replaced it. But it clearly fires enough to get a chug out of it.
Inline filter has flow, i haven't replaced it.

Not sure where to go. Obviously I can change the plug and filter, but are those likely to be the ones? Every time is fires and stalls is a carbon copy of the previous, regardless of what I do. I've put fuel directly into the cylinder, fed it quick start into the air intake, fed it quick start into the cylinder. Combinations of all three... Same thing BRAAAP-dead, walk away for five.

[Dick284]

Clean the spark arrestor screen.

[antlercarver]

I had same thing, plug looks good but when I put new plug in saw worked OK.

[CBintheNorth]

Originally Posted by Dick284

Clean the spark arrestor screen.

If equipped, definitely start here. Also check how old your fuel is and if it stinks.

Next I would pull the plug and see if it's wet. If so, I'd start by changing the plug.

While the plug is out, hold your finger or thumb over the hole tightly and check if it's building compression when you crank it over.

If there's compression I would put the plug back on the wire and dangle it in the hole, but don't thread it in. If it 'pops', then you know spark is good and there's at least some fuel.
Once we know the results of the above, we can probably help more.

[ghfalls]

Swap fuel and impulse lines as well. They’re cheap and not complicated to do.
Sawparts.ca is a good resource for chainsaw parts.

[Grizzly Adams1]

Originally Posted by Dick284

Clean the spark arrestor screen.

Fuel filter was my problem.

[Battle Rat]

Check fuel for tiny cracks.
Does it run with chock on half way?
Don't clean the spark arrestor, remove it and don't replace it.

[3blade]

Get a new plug. Anytime you are dealing with an unknown engine problem, just replace the plug first. Dont bother “testing” it, I’ve seen so many plugs deemed “good” by others end up being the source of the issue.

The fact that you’re getting the same result with putting fuel in directly should eliminate the carb. Other possibility is a blown head gasket. But I’d bet money on the plug.

[Double-Eh]

Final verdict:
Fuel line was pinched inside the tank.
Put in a new plug for good measure.
Currently working out the idle screws.
Already running great, gonna get it dialled shortly.

I think I could have figured it out for myself if I hadn't convinced myself months ago that all it needed was a carb kit. Sometimes you just need someone to point out where your nose is on your face.

Very appreciative guys!!

[CBintheNorth]

Glad it was something simple.

When I get some time I'll post up the story of my Stihl backpack blower. That was a doozy of a job diagnosing.

Had no idea they made a 4 stroke engine with no oil, but takes mixed gas...

[Unregistered user]

Originally Posted by Double-Eh

Final verdict:
Fuel line was pinched inside the tank.
Put in a new plug for good measure.
Currently working out the idle screws.
Already running great, gonna get it dialled shortly.

I think I could have figured it out for myself if I hadn't convinced myself months ago that all it needed was a carb kit. Sometimes you just need someone to point out where your nose is on your face.

Very appreciative guys!!

That is a common place to fail since the use of alcohol in gas, some of those plastic fuel pick up lines (LOL) will crack or break inside the tank causing the same grief. You can buy the stuff in spools from the jungle store, good to have some on hand. The best though most expensive option is to use Stihl premix. No booze in it. Or if you want remove the alcohol from your regular pump gas. Lots of youtube vids on how to.

[Dick284]

Originally Posted by Unregistered user

That is a common place to fail since the use of alcohol in gas, some of those plastic fuel pick up lines (LOL) will crack or break inside the tank causing the same grief. You can buy the stuff in spools from the jungle store, good to have some on hand. The best though most expensive option is to use Stihl premix. No booze in it. Or if you want remove the alcohol from your regular pump gas. Lots of youtube vids on how to.

It’s not just the ethanol in gas station gas that causes grief with small engines. Benzene being sky high in gas station gas is another killer in small engines, it wrecks rubber and plastics.

Here are a couple great YouTube vids explaining it all:
https://youtu.be/Wvps2gF0Sdo?si=1_aIz236JUfrgF-F
https://youtu.be/r9Hvg210ZAE?si=dNYberbOfcEGTE5u

[Unregistered user]

Good vids, thanx for posting.

[CanuckShooter]

Originally Posted by Dick284

Clean the spark arrestor screen.

I had saw problems a couple of weeks ago, and that's what my issue was. Only thing is I forgot that little trick and had to find it again on a google search.