Thread: 741-Baus - stihl chainsaw problem

Sounds like same symptoms of diaphragm being installed backwards.

Stihl use Stihl, Tilitson and Walbro carbs. If it comes down to it, you can replace the carb on that saw with an aftermarket walbro, which are available in Aus for about $50.00 delivered, in a size to fit that saw.
If it were me though, I would pull all of the fuel system down to component parts, clean thoroughly, and blow the carb body out with air. Blow back down the fuel lines as well. Clean out tank and reassemble. Ensure that pumping diaphram is installed correctly, so pumps from the pulse port side of carb.
Have you left old fuel in the tank? oil gum up in the carb can give similar symptoms as well.

Carl, I have to agree with Fossil on this one sounds like a carb issue ,but a few things first has it done this from new or has the problem surface over a period of time ,have you checked and cleaned the spark arrestor in the muffler normally I'd say just remove it but the reason that they were put in the first place is to stop red hot carbon shooting out and starting a brush fire !
With the stiff fuel hose when you turn the saw on its side with the fuel cap up does it run for a bit then cut out if so that would indicate that the hose is staying above the fuel level and running out of fuel , but again you have said that this is intermittent so perhaps not .
With the carb gaskets/diaphragms when you check them for stiffness put the fuel metering one the one with the metal tab in the middle up to your ear and move the centre from side to side if it sounds like a Rolf Harris wobble board click click click then its knackered and needs to be replaced buy a whole full service kit.when putting it back together fuel metering (needle side) goes gasket/diaphragm, other side diaphragm/gasket.
When cleaning carbs most people use carby clean and this does a serviceable job , I my self have bought an ultra-sonic cleaner and since getting and using it have yet to have a re-occurrence of the issues that brought it to me in the first place hard to start , when started wont keep running and I have yet to pull a welch plug to clean the small orifices under them
hope this helps Peter
Attachment 98041

sounds like water in the fuel tank either from condensation or some other way.

I had trouble similar to this with my 372 - would start ok, as soon as you pulled the throttle, she'd die unless you let go of the throttle quick. If you slowly pulsed the trigger you could get it up to full revs, but as soon as you touched timber with it she'd die in the backside.

Remedy was to change to a plastic fuel can (not those round bloody metal ones - these just manufacture condensation and your fuel gets buggered really quick) and blow out the fuel tank with compressor, clean out carby and she's been fine ever since

does it do it with a full tank

ok thanks for all the tips.

i have taken the carby apart many times and cleaned it. thayts what teh chainsaw mob said to do.

i keep all my fuel in plastic containers and use teh fuel for all my gear so i dont think its watter. i have drained the tank a few times also.

it dose it every time i want to use it.

if its really hot like iv been using it non stop for an hour it will start streight up. but if i leave it for more than 15 mins it will be back to its old tricks.

sometiems it wont runn at all and i add a bit of fuel and it will eventualy start.

am gettin really pi$$ed off with it.

would it be worth gettin a new carby?

or is it likely to be another problem.?

Hey Carl , pm me with your phone number and I'll give you a call ,
Peter