Stihl MS 460 dies after running 30mins intermittently

[mazurrj]

Since i got the saw it has died after using for 30mins or so, seem to be getting worse, today had to wait 2 hours, then ran fine. When it was not working it had spark, put gas in cylinder, i'm puzzled by this. i guess i should have taken back when was under warranty, di not happen that much though.
any ideas?

 

[Lakeside53]

Maybe your tank vent. Try loosing the gas cap when it starts to fail to relieve any vacuum. Does it fail "dead" or start acting up before it dies?

 

[mazurrj]

It does start to act up after a while and have to keep restarting by hitting button on top and putting swith all the way down, like would do for a cold start, then it will start, but then sometimes like today nothing will work , itoday i played with it for hour, emptied gas and refield gas, put new plug in. nothing, then came back couple hours later, started right up and finished my work in about 20mins. I'm going to try venting the gas and will check the vent though when dies. I could have multipule problems at this point. thanks for you're help.

 

[CaseyForrest]

Maybe a bad coil running open when it gets warm.

 

[Xtra]

I had a problem like that.
It ran fine after I cleaned the tank vent . . . it's a little black cap on the gas tank above the gas cap and has a bunch of little vent holes in it which became clogged with dust and gunk.

 

[mazurrj]

I'll definity clean the vent cap as i never have, going to look at spark when i 1st start to use so i can compare the spark cold and warm incase vent cap does not completly cure, i guess some winding on coil cold be shorting too when warm and maybe i'm just not getting full spark. Thanks everyone.

 

[toolmaker]

I take it you bought the saw new, because you mentioned warranty?
My dealer would probably look at the saw for me, and I bet he'd fix for free as long as there were no major parts involved.
You might want to try that.
This is why I go back to the same dealer all the time. Even if it is for incidental things like mix oil, bar oil, etc..
They remember repeat costomers and try to take care of them.

 

[mazurrj]

Maybe your tank vent. Try loosing the gas cap when it starts to fail to relieve any vacuum. Does it fail "dead" or start acting up before it dies?

Thanks Lakeside53 and Xtra, tank vent was the problem, ran long and hard today.

 

[Lakeside53]

Glad it was an easy fix... Tank vent problem are more common than thought.. lot of carbs get torn down for a simple tank issue.