MS361 issues

[otisdog]

I've got a MS361 that has very low hours, less than 25 for sure. It doesn't get much use because I don't have much 'big' wood to cut around my house. 026 and 028 can handle most of it. So i'm removing an ancient avocado tree that got fried in the recent 117 degree heat, and need the 361.
I know how to avoid flooding it while starting it, but I've definitely have a gas issue.
Filled it up, and let it sit out in the sun. Next day it had leaked 1/2 of the fuel tank. I've read the 100 or so threads on the saw, and hope you experts can point me in the right direction. Do you think the issue is a plugged fuel tank vent, bad gascap, or a needle valve issue?
Many thanks for the help.

 

[cuinrearview]

Your tank vent ain't venting.

 

[Chainsaw Jim]

Modern tanks do not vent, they hold pressure. Sitting in the hot sun allowed the fuel pressure to build until the carb reached its limit. Once this happens the fuel will escape into the cylinder and fill it up. The saw will cool off and the vent lets more air in to build up again the next time it gets warm.

 

[sunfish]

Filled it up, and let it sit out in the sun. Next day it had leaked 1/2 of the fuel tank.

^^^Don't do this.^^^

 

[otisdog]

Got distracted and forgot about it sitting out there. So all that fuel leaked through the carb?
How do I go about getting a service manual for this saw?

 

[Jed1124]

Pull the plug, turn it over and pull the starter cord a couple of time. Put the plug back in and fire it up.

 

[user 122190]

You probably have to steal one. Stihl is that way. Service manuals are good for finding specs, not so much in diagnosing problems. Youtube is the best way to learn how to DIY fix common (beyond is there gas?, or is the on switch on?, etc.) problems.

Got distracted and forgot about it sitting out there. So all that fuel leaked through the carb?
How do I go about getting a service manual for this saw?

 

[cuinrearview]

@AmericanPiddler is the guy you need. He's a YouTube saw guru.

 

[user 122190]

I'm sort of partial to the downblouse videos.

@AmericanPiddler is the guy you need. He's a YouTube saw guru.

 

[dmb2613]

smarter than a 5 year old

 

[otisdog]

Okay, I need to be clearer...prior to me leaving the saw in the sun, it still oozed gas. Sitting in the cool garage, when I pulled it off of the shelf, it was wet...even the muffler. This is with it not being used for quite a while. Pulled the plug, pulled the carb, pulled the muffler, blew it out with compressed air, put it back together, didn't run it and it would still be wet.
So....tank vent?

 

[otisdog]

bump

 

[Ozhoo]

So....tank vent?

No, check the fuel hose where it attaches to the carb. Once fuel begins to siphon, it will continue to do so.

 

[Chainsaw Jim]

Either the carbs metering lever is adjusted to high or there's an obstruction between the metering pin and seat.

 

[otisdog]

cuinrearview was correct...fuel vent was all lacquered up. OEM vent, all is well.

 

[Chainsaw Jim]

You can now leave it out in the sun all day after a cool night?

 

[otisdog]

Jim....my dog died that day.
Happy?

 

[jltrent]

Throw a new carb kit in it as it probably has had ethanol gas in it for and extended period and and the needle and metering diaphragm are bout shot. Very easy to do just be careful with the little spring and not lose and if you do it is not the end of the world .