Chainsaw smoke

[mrcommercial]

Hello, just did an engine swap on a Stihl Ms170...made one saw out of two. For about $60. So, when I start and/or throttle the saw up it smokes some. Not a whole lot like it’s got water in the fuel or anything, but it does put out a little . Any thoughts? I know there’re cheap saws but damned nice with a 14” bar/good chain on there. Light and cuts real good/quick.

 

[Little Al]

Hello, just did an engine swap on a Stihl Ms170...made one saw out of two. For about $60. So, when I start and/or throttle the saw up it smokes some. Not a whole lot like it’s got water in the fuel or anything, but it does put out a little . Any thoughts? I know there’re cheap saws but damned nice with a 14” bar/good chain on there. Light and cuts real good/quick.

What mix ratio is being used ? Also did you clean out the muffler being used is it from the old or 2nd motor & did you look /see to check if it's full of "gunge"

 

[mrcommercial]

What mix ratio is being used ? Also did you clean out the muffler being used is it from the old or 2nd motor & did you look /see to check if it's full of "gunge"

The lightest mix I use on anything that’s not a lawn boy is 40:1 or 50:1. The fuel in it now is either of those. The muffler is off the newer saw as is in good shape but I’ll clean whatever I find in there out. I’m just worried the carb boot may have a small crac in it etc, but thebsaw doesn’t act like it’s getting too much air? Just have to see. I may just take it to a good local saw shop I know of trying to stay away from hay as I’m wanting to be able to do most everything with these saws myself.

 

[Mustang71]

How much smoke are we talking about? Some of my saws smoke when cold. Most run rich under wide open throttle with no load on the bar. I run 40:1, ethanol free, echo oil.

 

[Little Al]

The lightest mix I use on anything that’s not a lawn boy is 40:1 or 50:1. The fuel in it now is either of those. The muffler is off the newer saw as is in good shape but I’ll clean whatever I find in there out. I’m just worried the carb boot may have a small crac in it etc, but thebsaw doesn’t act like it’s getting too much air? Just have to see. I may just take it to a good local saw shop I know of trying to stay away from hay as I’m wanting to be able to do most everything with these saws myself.

A suspected air leak wouldn't create smoke( smoke is usually caused by oil -to much of) I am not up on that particular saw but can the bar oil get to being involved in the combustion cycle ?If some of that is entering in the crankcase that would produce smoke.Have a look at the spark plug is it oily? if yes that would mean extra oil