I have a MS390 Stihl chainsaw and recently can't start it properly with the choke on/in neutral.

It will only start with the chain engaged and the motor will not idle - it stalls as soon as I stop cutting.

I can't find a user manual online for the model either.

Could it be that the choke needs adjusting/carb cleaning?

Ian Wingate, March 2009

sounds like the compression is down.remove chain and bar.remove exhaust and look directly into cylinder & piston any scuff marks or grooves on either ? if yes minimum cylinder and piston required (new)

plantman, March 2009

You should always start your saw with the chain brake engaged, so this isn't really a problem.

However, if this behaviour is a new thing something must have altered.

I'd guess it's the carb set up, possibly a blocked idle jet.

On most modern saws there is an interlink between the throttle lever and the carb. For a cold start the normal procedure is to put on full choke, pull the start cord until the engine fires, close the choke and then pull again - the engine should start and run - a little fast, as if the choke is on. 'Blipping' the throttle once the machine starts opens the choke fully and the machine should then settle to an idle. You shouldn't have to keep reving the engine to keep it going.

wes, March 2009