Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

roelex14

ArboristSite Lurker
Joined
Oct 11, 2011
Messages
27
Reaction score
8
Location
Central Illinois
I recently aquired a 038av mag. I was putting it through its paces on some soft cotton wood today. After about 3 or 4 passes through a 18 inch log, the saw started getting very hot and blowing a little white smoke. Virtually brand new bar and chain and is throwing plenty of oil off the bar. Running 50:1 gas:eek:il (stihl branded).

The heat seems to be coming from the exhaust area, but the cylinder is also very hot. It gets hot enough that I'm worried it may cause internal damage or the plastics may melt (get to the point they are untouchable) after running for extended periods of time... I checked to make sure the muffler was tightly seated against the cylinder and it was. I also dialed the high end on the carb back just to the point it doesnt bog down when ran wide open. Not finding much info on the interwebs regarding this issue.

Just wondering if anyone else has this issue or if this is normal for this saw; I've only ran newer saws this size so im not sure what the "norm" is...
Or what should be checked/fixed? I know basic small engine stuff, but my troubleshooting ideas have hit a dead end...

Thanks in advance for the help...
 
Saw is clean. Assuming/hoping its just a tuning issue. I reset the high and low tuning screws back to the manual recommendations (seated then backed out one full turn each). I'll have to wait until tomorrow to start it and run it again... dont think my neighbors will appreciate me trying to tune a saw at 9pm... ill see where I get maybe try to take a video and see what you guys think. thanks!
 
Saw is clean. Assuming/hoping its just a tuning issue. I reset the high and low tuning screws back to the manual recommendations (seated then backed out one full turn each). I'll have to wait until tomorrow to start it and run it again... dont think my neighbors will appreciate me trying to tune a saw at 9pm... ill see where I get maybe try to take a video and see what you guys think. thanks!
Plug color?
 
To me those setting numbers from the factory are a suggestion. They are only a starting point for me and I always tune the engine to a point I'm satisfied. The 1h+1l may be close or even good but you never know till you go rich and lean to find what's right for the saw/fuel/elevation/and desired use.
 
I bet lonewolf is right & your saw is too lean. Sounds like your carb tuning skills could be improved a little. Factory setting is just a starting point and may need considerable adjustment from that setting. My guess is a good half turn CCA is needed on the H needle. You NEED to know what four stroking sounds like and checking your plug is a good idea. A pic will enable others to help you out. Its fairly important to sort this correctly before putting your saw to work.
 
So I got it to where I believe it is 4stroking out the cut then runs smooth while cutting. But I'll let you guys be the judge: uploading videos shortly
 




Hope this works. the audio isnt great coming off my phone. Top plastic is still getting very hot after just a couple cuts... PS please dont mind my lack of protective gear, ive been in and out of the house trying to figure this out.
 




Hope this works. the audio isnt great coming off my phone. Top plastic is still getting very hot after just a couple cuts... PS please dont mind my lack of protective gear, ive been in and out of the house trying to figure this out.

What's your gas/oil mixture ratio you using? Sorry pal, I just read your earlier post. I assume 50:1 is correct for this saw. That's what I use for my all stihl equipment.
 
I have yet to pull the cylinder off, but could a bad piston and rings or scored cylinder cause this?
Not really sure, worn piston/rings might change heat transfer characteristics of engine, but probably not considerably.

Have you ever taken off the shroud - i.e. do you know how intact the cooling fins are? Are they clogged? Apart from tuning (which seems ok, but I'm no expert) that's all I can think of....
 
Pulled off the cylinder to inspect the piston and rings and walls. All look good... is this piece of casting on the intake of the port of normal... not sure how it would effect the engine temp but doesn't seem right.... 20160611_151828.jpg
 

Latest posts

Back
Top