MS390 dying out after five or so minutes of run time

[flying pig]

So I have an MS 390 here that runs fine for five or so minutes and then acts like it runs out of fuel. I've pressure/vac tested each of the lines and tank as well as the engine itself. Everything seems well. The pulse line is good, fuel line is good and so is the tank breather. It has strong spark when checked cold, but I haven't been able to check it hot when the problem is occurring. I'm more or less ready to just start parts swapping until I find it. I've had sleds do this where it's been a stator, they run good until hot and then die. Anyone know how to diagnose something like this in a saw? Also it has good compression and has been getting the same fresh premium fuel mixed with amsoil dominator like the rest of my two stroke engines get.

Any ideas?

 

[Magic_Man]

Check your tank vent.

 

[stihl_head1982]

swap the coil. That's the next check. You can probably get a used coil cheap.

 

[flying pig]

Vac tested the tank vent first thing, holds no vacuum.

Ok I'll see if I can get a coil, thanks!

 

[flying pig]

Do you guys know if there are resistance values I can check to verify it's the coil? My dealer wants $153 for one. I only have access to one or two other stihl saws to swap parts with as well, an old 026 and a ms 170.

 

[Mark71gtx]

Check it with the 026 coil. Aftermarket coils are cheap too. There is no way I would pay that much for that coil.