Decarboning fluid recommendation

[smiley]

I have a Stihl KM90R power head with an exhaust valve that refuses to seal. The unit is 4 years old and has less than about 60 hours on it. I have been using a 24:1 gas/oil mixture with non-synthetic oil. The exhaust valve turns freely when unsprung but will not seal after several hours of soaking with Mopar heat riser solvent , and then with SeaFoam. Any suggestions for a better solvent or other ways to clear the seat?

 

[Dub11]

Sounds like they need to be lapped.

 

[Stump Shot]

I cleared up a valve in a BR600 back pack blower by soaking it in 2-stroke oil overnight. Worked like a champ. I figured it would dissolve itself and it did.

 

[dustinwilt68]

Ultrasonic cleaner and mean green works also, may have to cycle it a few times though.

 

[smiley]

Thanks to each of you who responded. Dub11, your suggestion did the trick. I soaked the open valve and cylinder for 24 hours. The valve sealed after I blew it out!
Smiley

 

[Dub11]

Thanks to each of you who responded. Dub11, your suggestion did the trick. I soaked the open valve and cylinder for 24 hours. The valve sealed after I blew it out!
Smiley

Stump shot suggested that. I would of taken the thing apart and lost everything trying to lap the valves lol.

 

[brandonstclair20]

Echo red armor oil at 35:1 will de-carbon it in a hurry. it de-carboned my lawn boy mower but in the process fouled the plug twice


Sent from my iPhone using Tapatalk