Carboned-up 2-stroke, how to clean?

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I did a half-baked tuneup on my 23 year old Toro 2-stroke lawnmower today, and quickly found myself tearing the muffler off after replacing the spark plug. The inside of the muffler and the exhaust port were lousy with hard and soft carbon. It was caked on a good 1/8" in some places. It got chipped off where possible, but there's still a lot left in the exhaust port.

I was planning on running a TC-W3 2-stroke oil along with a little MMO and maybe a splash of PEA-containing cleaner in the gas this summer. It sounds like a little manual cleaning is in order, too. What's the best way to clean this stuff up manually/chemically?
 
You don't want anything solvent like in the fuel or it will brake down the oil and ruin it.......I would get out a small bush set and some brake clean o something like that
 
Sciphi, I can't offer any cleaning suggestions for carbon that serious, but I am curious what two-stroke oil(s) you ran in it that led to that much carbon over 23 years. I've never had a two-stroke engine for that long a time, so I don't even know if that's just normal carbon from 23 years use. Also, were you running spec. mix ratio, or something else?

Be careful with the in-gas fuel system cleaners. Most are designed for 4-cycle engines. I run them regularly in two-cycle engines, but I cut them down to 10% strength, from the dilution they call for, based upon Chevron's information about Techron Concentrate Plus' cleaners being 10 times the level in their gas. Since their gas has that detergent level, I figure I'm safe.

eg: instead of 1 oz. / gallon, use 0.1 oz / gallon.
 
Lawn Boy use to make a plastic tool for scraping carbon. You don't want to use anything made of metal as you run the risk of scratching the piston.
 
Johnny is on the right track.

I did some clean up work on a 1974 Lawn Boy last year. The muffler splits so it was very easy to scrape the carbon out of it and the ports were very clean.

to clean the exhaust port, get yourself a suitably sized hard wood dowel and use it to chip the the carbon off of the edges of the port. Try to minimize how much gets into the cylinder. Inevitably, some will get in. If you situate the piston so that it's just below the exhaust port, it should also be covering the intake port thus keeping debris in the cylinder. When finished, blow compressed air through the spark plug hole to blast the dirt out of the cylinder through the exhaust ports. Flush cylinder with WD-40 and blow more air until the cylinder is cleared.

Can the head be removed from the cylinder. If so, it should also be cleaned. It will also allow you to ensure the cylinder in nicely cleaned up as well after the port cleaning.

My LB and Tecumseh two cycle engines don't have removable heads so I pretty much have to use the method I mentioned above.
 
This mower was my late grandfather's. He ran whatever cheap 2-cycle oil in it he could find along with 87 octane gas for at least 15 years. The owner's manual says to run a TC-W3 oil and premium fuel in there. So that's what I'm going to do this summer. I ran premium in it last summer along with a little MMO, but with regular 2-stroke oil since the owner's manual only recently surfaced.

The cylinder head does come off. So that will be cleaned also.

Brake cleaner didn't touch this stuff. I tried with CRC non-chlorinated brake cleaner, and it got nothing off. Chipping with a dowel worked better.

Sounds like I'm making my first Amsoil order for some Power Foam. I've wanted to try that stuff anyhow, and this is as good an excuse as any.
 
I tried the blowtorch thing on my old Yamaha RD350 years ago. It didn't work so well... good excuse to buy some expansion pipes.

I wish I had known about SeaFoam back then. It probably doesn't do anything to remove the existing carbon, but I have an old Chi-Com Homelite string trimmer that I have always run SeaFoam in and there is no carbon build-up on the piston or head. That might also be due to better 2-cycle oil than I had in the early 1980's (I used Bardahl back then)
 
JASO FD oil is the best oil at preventing exhaust blockage. After the fact the best chemical to remove it is called EDTA for short, or Ethylenediamine Tetraacetic Acid. Set the piston in a position that blocks the port, and position the exhaust port straight up. Fill the port with the edta and let it sit for 6 to 24 hrs. After the soak a plastic scraper is all you will need to remove whats left over. It will make rock hard carbon like moist chocolate cake. Just don't be tempted to eat it. The msds is nasty.
 
From my experience, chemicals and snake oils either before or after the fact do nothing.

Here's a challenge for anyone out there. Take a carboned up piston or engine head and soak it in SeaFoam, MMO or any other magic elixir. Leave it in there for days if you wish. Watch to see what doesn't happen.

I've done it. Results.....nada.

Sorry to burst your bubbles but that stuff is next to useless and some of it is exorbitantly priced.

There is no substitute for elbow grease.
 
While I will agree with you on your test for SeaFoam, MMO, or any other magic elixir, the EDTA product 660mag is referring to does work as intended.
 
Tried it with seafoam, wd40, pbblaster nothing happens. As for EDTA you have no clue what your talking about. I suppose you think Ibuprofen does nothing too.
 
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:eek:il ratio and high rpms will keep most two cycle engines happy and clean for a very long time.
 
Low rpm, rich fuel, and poor fuel are without a doubt the main cause in 2 stroke ope. Stihl started using edta out of necessity in there 4-mix engines. The manual states the decard/vale adjustment as regular maintenance around the 130 hour mark. It was a tricky engine with new challenges. A 4 stroke engine that delivers the oil through the fuel system. If any of the running conditions you mentioned are there the interval is shortened considerably. The carbon is not an issue in the port of the 4mix but the exhaust valve itself. You would set the piston at tdc and turn the rocker nut so the exhaust valve was deep in the cylinder, fill the cylinder with edta and 24 hrs later readjust the valves dump it out and run it at wot of 5min. Carbon comes out in sparks and random clouds of black powdery smoke. That engine without a spark arrest screen would be a fire starter for sure.
 
Step 1 :

Carefully take apart cylinder from piston (digital camera your steps). If no mechanical damage proceed to step 2.

Step 2.

Soak metal parts in strong pail of carb cleaner for a day or so. scrub off softened deposits gently.

Step 3. Reassemble with new gaskets, fill up with fresh non ethanol gas and an ester based 2 stroke oil and enjoy .
 
Echo extended performance is easy to find. Home depot comes to mind. Any major handheld dealer will carry something fd. I read on here the lucas 2stroke oil is FD idn. You can find it at O'Reillys.
 
Good to know where to get good 2-stroke oil, and a good de-carbonizing product.

I'll try some stuff and see how it works.
 
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