MS361 No run

[Hogwildz]

Hogwildz, did you have this problem on a cold start or only when attempting to start after running it for a while?

Cold start, well sort of. Was already in the 40's when I tried to fire her up.

 

[Hogwildz]

This happened a couple years ago. I went to use it last year, and ran flawlessly. Ran this year so far great, then yesterday morn....nada. I just chalk it up to my saw being a temperamental biach at times. Fuel is fresh, I did mix at 50:1 and I was running on 40:1 and read the manual I downloaded offline that it takes 50:1. My next questions is low ash, ashless or regular oil? I know not to use the marine stuff.

 

[MasterMech]

Maybe I've had two bad/clogged breather valves! (Wouldn't be surprised.) The good thing is I haven't had a vapor lock in a very long time, and it's mainly because my SOP is to open the fuel cap for an instant after I've been running the saw for a long time. I still hear that sucking sound sometimes.

I use 93 octane gas from a supposedly reputable station and Stihl Ultra at 50:1 and keep it fresh. This summer I'll try a different gas station and see what happens.

Are you sure it's under vacuum and not pressure? Seems very likely there would be a bit of pressure in the tank after agitating a half-empty tank of fuel on a hot day.

 

[MasterMech]

My next questions is low ash, ashless or regular oil? I know not to use the marine stuff.​

I haven't seen a big difference as far as ash is concerned. I'd say less is more but with 50:1 (or leaner) mix ash is far less of a problem than it was back when we were mixing 30wt @ 16:1 for our saws.

Just make sure the oil is rated for air-cooled two-cycle engines. (usually marketed for chainsaws, trimmers, blowers etc) Some ATV oils are also good for the higher temps that air-cooled two-cycles see.

 

[TreePointer]

Are you sure it's under vacuum and not pressure? Seems very likely there would be a bit of pressure in the tank after agitating a half-empty tank of fuel on a hot day.

Good thinking--an incrreaase in temperature would make one consider liquid and gas expansion. I could be wrong, but what I observed felt and sounded like a low pressure (vacuum like) condition when I opened the cap. I get the sucking sound even on cool days when I consume a lot of fuel.

 

[MasterMech]

Good thinking--an incrreaase in temperature would make one consider liquid and gas expansion. I could be wrong, but what I observed felt and sounded like a low pressure (vacuum like) condition when I opened the cap. I get the sucking sound even on cool days when I consume a lot of fuel.

Shake a sealed gas can up (on any temp day) with 1/4 tank in it. Guarantee the sides will puff up or you will hear it go pssst as soon as you vent the can. The less fuel there is in the can, the more exagerrated the effect.

 

[TreePointer]

Shake a sealed gas can up (on any temp day) with 1/4 tank in it. Guarantee the sides will puff up or you will hear it go pssst as soon as you vent the can. The less fuel there is in the can, the more exagerrated the effect.

Heehee, I sure am familair with that. My 361 doesn't go "psssst" and blow the cap out. It actually doesn't want to give up the cap.until I pull it out of the saw body, and then it goes "tsss-thooooolk" like pulling a cork out of a wind bottle! .

 

[BobUrban]

And as long as you have the torch going, point it to the empty spark plug hole and spin the motor over.

I have used the "woof" technique to un-flood a motor many times but never a little motor like a saw. Mostly the lawnmower or equivelant.

 

[Jags]

I have used the "woof" technique to un-flood a motor many times but never a little motor like a saw. Mostly the lawnmower or equivelant.

Same - same. Really, it ain't doing anything different than what happens when it is running. If ya ain't ready it can make you jump back, though.