exhaust port carbon removal: Best Way?

Had the muffler off my 026 and the port had a lot of carbon chunks sticking to the sides. I made sure the piston covered the hole to the interior before scraping the carbon off. I vacumed out the carbon but pieces remained. Washed out with fuel mix and using q-tips got it clean. Do I need to do something else? Dump gas in the port and try and wash out the crankcase? Can carbon pieces get between the piston and the cylinder wall? I also need to clean a 15 year old 034 super exhaust port as well. Thanks for your help guys and gals.

On customers saws, I put the piston just below the exhaust port and scrape the carbon out. Some will fall into the cylinder, I blow this out with compressed air though the spark plug hole and re-assemble. Never had a problem doing it this way. Q-tips are a nice touch but probably over-kill. Run good oil and make all cuts at full throttle and you won't have a problem with coking.

Sedanman....Thank You!

Just curious, but what oil and mixture ratio are you using?

port cleaning

The carbon buildup was 15 years of using Stihl oil 40/50 to 1 and regular gas, 87 octane. Exactly what the manual called for .I thought it was 40 to 1 but the little 1 gal mix bottles say 50 to 1. Don't know what year they changed it. I have now switched to Mx2t 32 to 1 and 91 octane. Will see what it looks like in another 15 years. I should have taken a picture before I cleaned it and you could have told me if it was normal! Thanks!

Not to slight Sedanman, but carbon is very abrasive.
The best way to decarbon a cylinder is to remove the cylinder and use Mercury marine powertune or low temp oven cleaner. Once the powertune has sat on the carbon for awhile it softens it up to a putty like consistancy. Then you can remove it with a hardwood dowel with the end ground down to form a scraper of sorts.
FWIW two cycles today with modern, high quality oils rarely need to be decarboned. The exception being Lawnboy mowers.

That would hardly be worth it especially on a lot of engines that thy cyl. is integral with the upper crankcase. I think the risk of a bit of carbon less than disturbing all the hoses, gaskets, and fasteners to remove the jug unless you really have to decarbon the combustion chamber. Chainsaw not helicopter! Lol!

Frank, it takes, what, maybe 20 minutes to get the jug off? Id rather take the time to do it right than to risk damging the piston.
Besides, like I said before its fairly rare that it needs to be done nowdays.

If you have the jug off anyway, its the time to give the exaust port a shining to help prevent the same thing happening again. Also the piston top and head space likely look much the same as the exaust port and will need a clean anyway.

as said above it,s only a 20 min job, if you dont have strong finger nails you may need to make a ring compressor out of a beer can ect. Care must be taken to make sure the rings are aligned for reasembly with the alignment pins in the piston ring recesses.

Ben and Timberwolf, I am still with Sedanman. The question was cleaning out the exhaust port. First thing is if you have to ask you very likely shouldn't be going further than he suggested. You guys are giving good advice for someone who wouldn't need it, Lol! I bet Fish would agree with me!

Since Fish does not post much, right now I agree with you, Frank.

Seriously, I think Sedanman is right on! This is how I do on the old bears.
The newer is run with non carbon fuel!!! :blob5:

Mange, Non Carbon Fuel??????!!!!???? What on earth are you talking about?

Ben and Timberwolf, thanks for the tips, at least you are giving the rest of us the story on the best way to do things.

Alkylate fuels, Aspen etc.

Mange, you just cant beat that straight hydrogen for clean burning!

I have seen lots of oops! projects wind up in the dumpster because someone went in over their heads, took everthing apart and missassembled. Different screw lengths, impulse holes plugged by gaskets, improper torque, flange ears broken, rings broken, washers dropped into crankcase etc.
It is only in recent years that some of you guys actually started to fix most of the stuff you took apart and are starting to get cocky because you are forgetting about your scrap heaps! lol! Experience is a wonderful teacher, but it is not the cheapest.

Frank, out of all the mechanical things I have ever worked, I cant think of one any more simple than a modern chainsaw. If someone would screw up a simple jug removal its very likely they cant chew gum and walk and would likely get alot of carbon into the cylinder doing the job with the jug on.
BTW Mange, Alkylate is a hydro carbon.....Av gas is a alkylate based fuel fwiw.

I asked this before in an other thread, actually it is in 3 threads, and no Alkylate based fuel was availeble in US.

No fuel like Aspen is availble in the USA to the best of my knowledge. That is to say no pre mixed fuel sold for chainsaw use is available.

Here is a link in regards to alkylation.
http://www.chevron.com/prodserv/fuels/bulletin/aviationfuel/11_ag_refining.shtm

I thought jugs were hooters

Thanks for all the help guys. Sedanman and Crofter guessed my level of mechanical ability. I asked the question because I didn't want to screw up a great saw. I get not dropping stuff into the crankcase. But what is an impulse hole?, or flange ear? Is the Jug the cylinder? Are we still talking about an engine? Take the rings off with a beer can? I think I would like to see someone do this first so I have a clue what to do. Not having a compressor, will a can of compressed air work? Chew gum and walk AT THE SAME TIME?

Great info there, Ben.

I am sure it will come eventually, as it is a good thing after all, a bit expencive but well spent money.

http://www.chevron.com/prodserv/fuels/bulletin/aviationfuel/pdfs/chapter11.pdf

Mange said:

Great info there, Ben.

I am sure it will come eventually, as it is a good thing after all, a bit expencive but well spent money.

http://www.chevron.com/prodserv/fuels/bulletin/aviationfuel/pdfs/chapter11.pdf

Click to expand...

Not sure about the U.S, but here I seriously doubt insurance companies, governments and Fire Marshalls presently would allow fuels such as ASPEN to be retailed in any place except approved gas stations. Not really sure how big the market would be for it and if petroleum companies would warrant such carrying expense.

Now as it does burn cleaner and pollute less if the EPA were to get involved, nahh forget it, do not want to go there !