Help Identify this Stihl saw

[KennyPete]

I took this MS390 on trade a while back, finally getting around to working on it. Previous owner said it wasn't oiling correctly and cut like crap.

First thing I noticed was he was using a 3/8 B&C with a .325 sprocket. Replaced with .325 B&C. Oiler was working fine, just needed turned up a little.

Now the problem - He handed me a spare P&C with it, brand new in the box - said he got it from his brother who was going to rebuild a saw he had, but the saw got lost during a divorce. On the box it was labeled for a 290 and I verified that it is a 46mm.

Between the .325 sprocket and this spare P&C, I am questioning if this is indeed a MS390 that he sold me, or if it is a 290 that he replaced the badging on.

Serial number is 253591909

Could someone please look it up for me and find out if it is indeed a 390?

I tried calling my local Stihl dealer and didn't get anywhere. I would rather not pull the saw apart just to figure out what it is. Thanks in advance.

 

[heyduke]

I took this MS390 on trade a while back, finally getting around to working on it. Previous owner said it wasn't oiling correctly and cut like crap.

First thing I noticed was he was using a 3/8 B&C with a .325 sprocket. Replaced with .325 B&C. Oiler was working fine, just needed turned up a little.

Now the problem - He handed me a spare P&C with it, brand new in the box - said he got it from his brother who was going to rebuild a saw he had, but the saw got lost during a divorce. On the box it was labeled for a 290 and I verified that it is a 46mm.

Between the .325 sprocket and this spare P&C, I am questioning if this is indeed a MS390 that he sold me, or if it is a 290 that he replaced the badging on.

Serial number is 253591909

Could someone please look it up for me and find out if it is indeed a 390?

I tried calling my local Stihl dealer and didn't get anywhere. I would rather not pull the saw apart just to figure out what it is. Thanks in advance.

put a drinking straw in the exhaust port. bring the piston up just enough to mark the straw. remove the straw and measure the bore.

 

[old guy]

Or if you have a dial caliper, but the tail end of it against the piston in the exhaust port then open the caliper till the pin touches the other side of the cyl. and read the dial.

John

 

[KennyPete]

Thanks for the help guys. Took the exhaust off and measured it using a dial caliper like John said. Good call.

It is indeed a MS390.