Originally Posted By: 660mag
Sorry, that was rude.
No offense taken.
I must admit that I've not tried the EDTA and likely won't. I prefer to disassemble two cycle engines for complete cleaning if and when necessary. Personally, I don't see a lot of carbon build up even on very old engines.
In the last couple of years, I've rebuilt three two cycle air cooled twin cylinder Yamaha motorcycle engines. One engine ('76 RD400) had been very much abused and needed to be completely rebuilt from the crank up. It had injested lots of dust and was pretty much worn out. Crank seals leaked and the thing would run away something awful. When I tore it down, the only place with any real accumulation of carbon was the rings. They were completely baked solid with carbon and probably dust too. I took each piston and soaked the crown/rings in various fuel additives. Nothing happened.
I also pulled apart two RD350 engines that were in excellent shape for being 36 years old. Some discolouration on the piston crowns and cylinder heads but no carbon build up. Even the exhaust ports were clean.
I took apart a '74 Lawn Boy engine last year. It was in fantastic shape internally and I doubt that it had ever been apart before. Had some carbon build up in the muffler but the exhaust ports were in great shape.
I also opened up a 1980s Stihl 034 chain saw last year and internally, it was in great condition. Not even any carbon in the muffler.
This year I also opened up a 139cc Tecumseh two stroke engine on 1997 snow thrower. Clean as a whistle and it runs fantastic. I've got a governor over-ride on it and can use it like a throttle. I spin that engine anywhere from 3600 to 6000 rpm and when under load run it steadily between 5000 and 6000 rpm. When I pulled off the muffler, I was surprised to see how clean it and the exhaust ports were.
I see the insides of a lot of two cycle engines and I'm not sure what would cause certain engines to accumulate so much carbon in other people's engines. Probably from running too much oil and too little engine speed/insufficient operating temperature. The correct fuel
il ratio and high rpms will keep most two cycle engines happy and clean for a very long time.