365 husky tar coated piston and cylinder

[subhunter]

I just pulled apart a 272 that looked like it had tar all over the baerings and the crank. The bearings seemed to still spin smoothly but were just really nasty.
The crank has been sitting in gas for two days now, later I will see how it cleans up. FWIW the combustion chamber and the EX port are both severely coated in some thick carbon..

 

[baotman]

365 all tar coated

Orange or white bottle Stihl oil? I've heard of not seen problems with one of them carboning up real bad. I would try some laquer thinner and a putty knife.
Shep

The stihl oil Im useing is the universal type made by stihl. I buy it by the gallon jug ,and mix what ever mix I need to use it on. I do have alot of different equiptment. Just a question I never seen oil go bad just sitting in a sealed jug ,cuold it be possible ?????? thanks baotman:baffle:

 

[baotman]

365 tar coated piston and cylinder

I just pulled apart a 272 that looked like it had tar all over the baerings and the crank. The bearings seemed to still spin smoothly but were just really nasty.
The crank has been sitting in gas for two days now, later I will see how it cleans up. FWIW the combustion chamber and the EX port are both severely coated in some thick carbon..

Hi guys
I give my saws no mercy when I run I stand on the throdel and cuts very well .I do not llike to bog a saw down it doesnt do them any good at all but load them up . Also i took the spark arester out for better flow . thank baotman

 

[barneyrb]

Just thinking out loud but what are the chances of bar oil seeping into the crankcase?

 

[tree monkey]

Just thinking out loud but what are the chances of bar oil seeping into the crankcase?

maybe

 

[mowoodchopper]

are you sure the stihl oil in the gallon jug dosent say bar and chain oil

 

[tree monkey]

View attachment 214318
does it look like this? stuck ring?

 

[Axlerod74]

are you sure the stihl oil in the gallon jug dosent say bar and chain oil

AaaaaaaaaHHHHHHHHHHHH!..........................UNIVERSAL oil. :waaaht:

 

[tree monkey]

its from the fuel. 1 gal of gas lasts all summer in a trimmer, or gas from the summer before.

gas does not go bad ya no.

 

[hamish]

View attachment 214318
does it look like this? stuck ring?

So the excess carbon deposits and resulting blowdown past the ring are all from the fuel??

Not likely. Is the piston in the photo in question sticky with like a tar like substance, I doubt it. Most likely the piston in the picture you have posted is from yet another one adding a lil of this and lil of that and messing up the fuel/oil ratio (not the fuel mix/air ratio).

 

[tree monkey]

yes the piston was sticky tar when it was removed.

ive tore down saws that were using very cheap oil that were very clean inside, loggers saw
ive tore down saws that were using oem oil from new that were black from the piston to the case, home owners saw

its the fuel

 

[baotman]

365 piston and jug coated in tar

Hi guys
I saw the picture that Tree Monkey posted , looks just like it only a little worse .You hit the nial on the head tree monkey thanks. I usualy get gas at speedway .Is there something in the gas that is causing this ? Look forward to hearig back from you guys thanks baotman

 

[hamish]

yes the piston was sticky tar when it was removed.

ive tore down saws that were using very cheap oil that were very clean inside, loggers saw
ive tore down saws that were using oem oil from new that were black from the piston to the case, home owners saw

its the fuel

Well if its the fuel then, tell us why?

Yes it is a fuel issue but more of a fuel/oil mix issue.
The OP is asking for help, we all want to do our best to help him out, if you have a theory throw it out there with a lil bit more than "its the fuel".
If you think its fuel related why? what should he be checking? Was it the ethanol he started using 3 weeks ago that loosened up existing carbon deposits in the saw? Was it.....throw the man a bone.

 

[tree monkey]

its called coking, and is caused from old fuel that burns too slow/cold

i did

 

[parrisw]

i did

LOL

Here is something that will tell anyone who wants to try it. Take some old gas pour in in a line on some metal, take some new gas do the same, make both lines the same length, light it, see what happens.

 

[hamish]

When the op stated he used good fresh gas....................

Coking is just a buildup of unburnt carbon, been around for near ever, back in the early 80's rotax called for ring and head cleaning every 50hrs, nothing new there save for ethanol was not present at the time.


Its alot more than just the fuel going bad, its air/fuel management, air fuel mix etc....not just the fuel.

 

[baotman]

365 all tar up

Hi guy
Thanks for the info on cokeing ,I do have a question would leaning out the top end help ? You said it was a air flow issue just wondering if I should make it scream or back it off just a little on the full throdel thak again baotman:cool2: