chainsaw quits

[rvhop]

Hello to eveyone, I have a sthil MS290, yesterday I was cutting some bushes at the edge of the yard. The saw cranked fine and ran fine for about an hour. I was cutting a privacy bush when it went dead. When it died it wasnt a smothering down. It was like the switch was cut off. I checked the gas and was far from empty. This morning I was going to cut some more. The saw wouldnt start. I checked the sparkplug, the fire was fat but not a blue color (yellow). I went and got a new plug and still not starting. I would appreciate it if someone would tell what to look for and how to troubleshoot. Thanks to everybody, rvhop

 

[MarkV]

Couple of things I would check, air filter, fuel pickup filter that is in the tank, fuel line (new ethanol gas is doing bad things to them). If you are getting spark it doesn't sound like the switch so I would look at fuel system. I'll assume you were using fresh gas if cutting for an hour.

MarkV

 

[JimRB]

I did a gasket set in a carb a few weeks ago. I also did fuel lines and grommets at the same time. The fuel line in the tank was collapsing. This happened to be a Stihl hedge trimmer which refused to idle. It has a smooth idle and starts quickly with new gaskets and fuel lines. Actually I did fuel lines and grommets first but it would not start easy or idle. New carb gaskets as the diaphragm for the fuel pump was a bit hard and was probably the problem.

 

[newbury]

What he said and
OUTSIDE Pull the plug, put choke on full and crank, is mix coming thru? (you'll smell it)
Does it fire? Take the filter off for testing. If it was getting mix let it dry out and then put in a few drops of mix thru the plug hole. Quickly replace plug and crank it. If it fires briefly the lines may be bad.
My fix for that is get Seafoam thru the system until it fires and runs.

Pull the muffler and see if the piston is scored.
Check compression.
good luck with a good saw

 

[LD1]

Any update? Did you get it running?

 

[g0rd0]

open your saw and with a tooth brush clean all of the sticky saw dust off of the contacts on the switch, give the switch a blast of compressed air to dry it off and start. if that dosnt work replace the switch

 

[LD1]

open your saw and with a tooth brush clean all of the sticky saw dust off of the contacts on the switch, give the switch a blast of compressed air to dry it off and start. if that dosnt work replace the switch

Some feedback from rvhop would be great, but it most likely isnt the switch since he said he had good spark. Most likely fuel delivery issues, but without feedback....:confused3:

 

[rvhop]

Thanks for the input. I took off the air filter and blew the sawdust off. I tried to crank the saw with the air filter off. I pulled the plug and poured a little fuel in hole , replaced plug and still no start. What else should I do.

 

[LD1]

If you are POSITIVE you are getting good spark, AND it still wont fire with about a cap-full (20oz bottle cap) of fuel poured straight in, then I am afraid it is time for a compression test. Cause IF you are getting good spark, AND fuel (via dumping straight in), then the only thing left that it can be is low compression. Either a worn ring or scored piston/cylinder.

If you dont have a compression tester, you can start by taking the muffler off and looking at the piston. You'll know if its bad.

 

[rvhop]

I took the muffler off, i think the piston looks o k, but the crankshaft does make a full revolution. The piston moves up and down, but at a certain point it locks up. I believe its had it. Again thanks to all you guys for your help,

 

[LD1]

Can you get any pics of the piston with the muffler off??

If it is indeed the issue, with it being a MS290, if it isnt under warranty, it probabally aint worth fixing. But you might get lucky, if the cylinder isnt hurt and it just needs a piston and ring, it might be worth fixing IF you can do it yourself. A piston and ring kit is usually around $50. But if you need the cylinder, it goes north of $100 quickly for a good one.

 

[xyz123]

I took the muffler off, i think the piston looks o k, but the crankshaft does make a full revolution. The piston moves up and down, but at a certain point it locks up. I believe its had it. Again thanks to all you guys for your help,

WAG time. Did your coil come loose and hitting flywheel? I fixed one the other day that did this.

 

[Gator6x4]

Take the new plug you said you installed out and see if the engine will rotate. Sounds like you put a plug with too long of a reach or tip in the saw. You could also have a large piece of carbon that has broken loose and is now jamming against the top of the piston. If the engine will rotate take the old plug with you and buy a new one. Remove the filter and squirt a small tablespoon of gas through the throat of the carb directly into the combustion chamber and immediatley try to start. Also place a paper towel on the muffler and see id you can blow through it. A clogged muffler will prevent the engine from starting or running. Also most two strokes want a muffler installed before they will start and run.

 

[rvhop]

The coil is attached good. I took the plug out and the flywheel only rotates about 180 degrees. The piston moves freely up and down. I believe the crankshaft has a bad bearing.

 

[LD1]

Is their any signs of the coil coming into contact with the flywheel?

 

[rvhop]

No the flywheel and the coil have the right spacing between them.

 

[LD1]

Sounds to me like its time for an exploratory tear-down:thumbsup:

 

[cheif]

CONNECTION ROD BOLTS COM LOOSE IT HAPPENED TO ME ON A SMALL HUSQVARNA

 

[CobyRupert]

How do you get good spark if the crankshaft doesn't make a full revolution?