Chainsaw Smoke

[Deleted member 168049]

Pull the muffler and post a photo of the side of the piston as seen from the exhaust port.

Your photo above might be just carbon build up from improper running. Once it runs properly it will burn off.

Might take a minute to process to decent quality, just been uploaded



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[farmguywithasaw]

Wow that exhaust port looks very oily. The gas you mixed for it I assume you use it in other things without issue? It seems to me that is way more than 50:1

 

[farmguywithasaw]

Oh and clean the exhaust port you can see carbon scores starting on the top of the piston

 

[Deleted member 168049]

Wow that exhaust port looks very oily. The gas you mixed for it I assume you use it in other things without issue? It seems to me that is way more than 50:1

I've been using it in my strimmer for the past few days, very slightly smoky but showing no issues whatsoever.

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[farmguywithasaw]

Did you have the saw tore down at all. Remember what I said about the gas evaporating and leaving all the oil sludge. It’s possible that it could have did this in the crank case. I worked on a saw that my neighbor said was running fine and the next day was stuck. What it was is it was very hot out and the carb needle didn’t seat so the pressure in the fuel tank pushed all the gas into the saw and filled the crankcase. Could of had something similar happen and then dried out leaving sticky oil int the crank case. Was it hard to turn over when you got it?

 

[SteveSr]

Saw has either got too much fuel or wonky ignition that fires every 2-4 revolutions.

Have you pressure tested the fuel inlet on the carb yet? If you don't have a Mity-vac you can use a sports ball pump with a good low pressure gauge or possibly bicycle pump and a little ingenuity. The main favorable result = NO leaks!

Any chance that you can borrow a known good coil from another similar saw for testing purposes?

 

[Deleted member 168049]

Saw has either got too much fuel or wonky ignition that fires every 2-4 revolutions.

Have you pressure tested the fuel inlet on the carb yet? If you don't have a Mity-vac you can use a sports ball pump with a good low pressure gauge or possibly bicycle pump and a little ingenuity. The main favorable result = NO leaks!

Any chance that you can borrow a known good coil from another similar saw for testing purposes?

Someone else has mentioned the ignition coil so it's looking beneficial to replace it.

As for pressure testing, I quite honestly dont have a clue how to pressure test any part of the saw

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[farmguywithasaw]

In the video it seemed to run ok to me. Have you made any cuts with it?

 

[SteveSr]

As for pressure testing, I quite honestly dont have a clue how to pressure test any part of the saw

Now would be a good time to learn... Remove the carb from the saw. Find or borrow a sports inflator with a gauge on it. Connect the sports inflator to the fuel inlet on the carb with suitable hose/tubing. Pressurize to 7-10 PSI and see if it holds.

If it doesn't hold pressure dunk it in a glass of water and look for bubbles!

 

[SteveSr]

@HarleyT Take a look at the video in the first post. Does this look like it could be a bad coil only firing every couple of revolutions? Any other ideas?

 

[HarleyT]

@HarleyT Take a look at the video in the first post. Does this look like it could be a bad coil only firing every couple of revolutions? Any other ideas?

Looks more like a carb that is running very rich, for some reason. I would suggest that he dump out all of the fuel, then take a video of the saw burning the last bit of fuel out of it. I think that you would see it run extremely well there as it was burning off the last of the fuel, that would at least confirm the running rich theory.

 

[SteveSr]

Looks more like a carb that is running very rich, for some reason. I would suggest that he dump out all of the fuel, then take a video of the saw burning the last bit of fuel out of it. I think that you would see it run extremely well there as it was burning off the last of the fuel, that would at least confirm the running rich theory.

Yea, that wouold be a good way to rule in/out the ignition. Warm it up, dump the gas, set it to part throttle (starting position), start the video, start the saw and see what happens