Chainsaw not going right

new2me

Got an 028 stihl that wont start until I spray carb cleaner into the carburettor and then it starts but after 8-10 minutes running loses power and conks out.
Any ideas guys on what’s wrong, new filters, oil. Fuel and plug.

new2me

new2me wrote: »

Got an 028 stihl that wont start until I spray carb cleaner into the carburettor and then it starts but after 8-10 minutes running loses power and conks out.
Any ideas guys on what’s wrong, new filters, oil. Fuel and plug.

Does it only start with carb cleaner? Check the compression (cold saw) and use a cable tie to hold the throtte open while you do it. It should be okay if it runs for 10 mins I suppose. Check it to be sure and tell us what the reading is in PSI.

If it’s good, put a full carb set into it, needle jet, roller pin, diaphragm and gasket. It could be causing the trouble (or some of it) so just do it if it’s more than a couple of years since done, or even less if using normal petrol and oil mix.

For the cutting out, assuming the carb is done and doesn’t fix the problem:

Does it start again within a few minutes, or right away if you’ve opened the fue tank cap?

Will it run for another 8-10 minutes before cutting out again?

If so, fuel tank breather is suspect #1. Do you hear a sucking noise when it cuts out and you open the filler cap?

new2me

you cant start it without carbs,then will run for 5 minutes now and lose power and go off, it will start again but only for 10 seconds then shut off again, no sucking noise

its 16 years old and probably needs a new carburettor, hate to part with it as it was a brilliant saw

new2me

new2me wrote: »

you cant start it without carbs,then will run for 5 minutes now and lose power and go off, it will start again but only for 10 seconds then shut off again, no sucking noise

its 16 years old and probably needs a new carburettor, hate to part with it as it was a brilliant saw

Rebuild the carb with a genuine kit (Tillotson or Walbro, depends on what's in your saw but I don't think new genuine carbs are available) and if you aren't keen on your ability to do it right, give it to a saw shop to have it done. Get them to put a new fuel line in while they're doing it.

Otherwise, you can get an aftermarket carb here:

https://www.ebay.ie/itm/Carburetor-Carb-For-Stihl-028-028AV-Chain-Saw-Super-Tillotson-HU-40D-Walbro-WT-B/282753471317?hash=item41d56b9355:g:hXoAAOSwdjdaHram

Don't bin your genuine carb. If you put that pattern carb on and it solves your problem you can always get the genuine one rebuilt. In any case get new gaskets (to cylinder and air filter housing) and make sure you put a new fuel line in while you have it all apart.

16 years isn't old and if you like the saw and know the rest of it is grand, you'd be mad to get rid of it for want of a kit/carb.

EDIT to ad, I would bet on it being the pump diaphragm is gone too soft or the needle or lifter are worn out and she's starving. Either way, a carb rebuild would fix that.

new2me

thanks actually started it there now with carb cleaner and fired up but now once you give it any revs its loses power and shuts off

Thepillowman

Sounds like diaphragms gone get a rebuild kit for the carb. If you can clean carb in an ultrasonic cleaner. Handy way of checking compression is to hold saw by the starter rope it should drop in a slow jerky movement. If it drops fast compression is low. As for the fact saw is 16yrs old if compression is good there is lots left in it. I have a saw that was bought in 1963 that can still do a days work.

Thepillowman

Thepillowman wrote: »

Sounds like diaphragms gone get a rebuild kit for the carb. If you can clean carb in an ultrasonic cleaner. Handy way of checking compression is to hold saw by the starter rope it should drop in a slow jerky movement. If it drops fast compression is low. As for the fact saw is 16yrs old if compression is good there is lots left in it. I have a saw that was bought in 1963 that can still do a days work.

An 028 with good compression shouldn't drop at all if held up on the starter.

I just thought of something else worth changing while you take stuff apart. Those Stihls use an external impulse line to drive the fuel pump in the carb. Change it also.

Edit: Here's a couple of good videos for you from a good fella for this kind of job:

Nekarsulm

Pillowman, what 1963 saw do you have?

new2me

thanks guys, i have a new carb coming so what else should i change when im installing this

I'd put a new fuel line, impulse line and fuel filter into it.

Be really critical in your inspection of the intake boot. That's the rubber coupling that connects the carburetor to the intake on the cylinder. It should have no signs of perishing or cracking at all. If it does, put a new one on it because an air leak there could cost you the saw (cylinder/piston/crank) if it leans out. You might catch it, you might not, that's for you to decide but if it was me I'd just put a new one in while I have the saw apart.

Thanks for coming back to let us know what's happening. Always nice to get an update

new2me

JayZeus wrote: »

I'd put a new fuel line, impulse line and fuel filter into it.

Be really critical in your inspection of the intake boot. That's the rubber coupling that connects the carburetor to the intake on the cylinder. It should have no signs of perishing or cracking at all. If it does, put a new one on it because an air leak there could cost you the saw (cylinder/piston/crank) if it leans out. You might catch it, you might not, that's for you to decide but if it was me I'd just put a new one in while I have the saw apart.

Thanks for coming back to let us know what's happening. Always nice to get an update

thanks, you know i might change that too just in case, hardly that expensive to buy,
by the way is there much stripping to get to this

have2flushtwice

Interested how you get on with this one. What prices a rebuild kit, ice an old sthil and she won't go at all. Wont fire. A kit and a plug and a fuel linenwill tell a lot.

new2me

new2me wrote: »

...
by the way is there much stripping to get to this

Only saw this now. Don't know how much stripping as I use the orange swedish saws myself. Those oul German yokes give awful trouble with carburettors or so I'm told

Can't be much to it I'm sure. Can you get an exploded diagram for it maybe? If you have a Stihl dealer near you maybe they'd be helpful and give you a look at it or a printout. But it can't be too tricky anyway. Take pictures as you go and don't force anything and you should be right in no time.

Thepillowman

Nekarsulm wrote: »

Pillowman, what 1963 saw do you have?

Sorry for late reply it's a Contra/Lightning.

Nekarsulm

Thepillowman wrote: »

Sorry for late reply it's a Contra/Lightning.

Very nice!
Never had one, nearest I've got is a Solo Rex.

This popped up in my YouTube feed recently...

https://m.youtube.com/watch?v=CL9FlIYye4I

Thepillowman

Nekarsulm wrote: »

Very nice!
Never had one, nearest I've got is a Solo Rex.

This popped up in my YouTube feed recently...

https://m.youtube.com/watch?v=CL9FlIYye4I

Seen that the other day as well it's impressive. Love that sound.