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View Full Version : What's the best way to de-carbonize a 4 MIX engine?


john_incircuit
08-21-2007, 02:57 PM
What is the proper / best way to de-carbonize the 4 Mix engine? I just set the valves and changed the spark plug for the first time, was surprised how much carbon was on it.

I read that Stihl has a special fluid for the de-carbonizing, but does it go in through the spark plug hole or through the exhaust port, should the valves be closed or open during the cleaning ... if the muffler has to be removed, do I have to use anti seize when reassembling ...

Thanks!!

mcdc6
08-25-2007, 08:19 PM
go to your stihl dealer and ask for the instructions that come with the de-carbonizer. but the valves need to be closed and the fluid goes into the spark plug hole and the replace the spark plug and let sit for 8-12 hours the drain.

G.M.Landscaping
08-25-2007, 08:46 PM
When are you supposed to do this? I bought my fs100x at the beginning of last year, but I only cut 2 days a week. I thought it was at 100 hrs your supposed to do it.

Maybe it's time I do this.

fixer67
08-25-2007, 08:56 PM
Do not get that de-carbonizer on your skin it will burn. It will turn the carbon to a paste like mess. Becareful not to let the paste mess get down into the engine when you clean it up.

fixer67
08-25-2007, 09:03 PM
Do not get that de-carbonizer on your skin it will burn. It will turn the carbon to a paste like mess. Becareful not to let the paste mess get down into the engine when you clean it up.

fixer67
08-25-2007, 09:05 PM
For some reason my post doubled. Feel free to delete post 5 (copy of 4) and post 6 (this post)

SILVERSTREAK INC
08-28-2007, 12:36 AM
rev the motor full throttle and spray some h2o into it from a squirt bottle, gets rid of all the carbon baby

john_incircuit
08-28-2007, 01:52 PM
rev the motor full throttle and spray some h2o into it from a squirt bottle, gets rid of all the carbon baby

You must have driven a muscle car years ago... I guess this could work, but I'm not sure if I'm man enough to try this out on the 4- Mix

Fairway Land & Lawn
08-28-2007, 02:09 PM
I know it is tough with a string trimmer.....the four mix engines like to be run at WOT. My neighbor works for Stihl and tells me to run them all wide open. I have a Br550 that has well over 250 hrs on it and have never had a carbon problem. Run the string trimmers wide open for about 2 minutes at the end of the day, should get a cylinder temp to burn the carbon up...just my 2 cents....

HenryB
08-28-2007, 02:34 PM
rev the motor full throttle and spray some h2o into it from a squirt bottle, gets rid of all the carbon baby

How do you do this? Through the carb?:confused:

EMJ
08-28-2007, 08:57 PM
Mercury Marine use to sell a product called power tune. We sprayed in the carb at full throttle and it removed the carbon. I do not know if they still sell it though.

xxl
11-23-2007, 11:36 PM
sea foam works good did it on pruner

Stillwater
11-24-2007, 02:41 AM
throttle body cleaner

Jay Ray
11-24-2007, 09:20 AM
rev the motor full throttle and spray some h2o into it from a squirt bottle, gets rid of all the carbon baby

I was always told you risk pitting the combustion chamber and top of the piston with this method.

topsites
11-24-2007, 11:20 AM
Me I just run super, I do not know these problems unless it's running too rich?
A lot of that black soot is as likely petrol contamination, both dirt buildup from petrol contamination and soot looks black.
True soot is made of carbon, that comes from running too rich, a dirty air filter would contribute as one example.

Several tank fulls of a pure acetone mixed in with fuel might do it, 3 ounces acetone per 10 gallons fuel.

Stillwater
11-24-2007, 11:34 AM
I was always told you risk pitting the combustion chamber and top of the piston with this method.

don't run regular gas in stihl products
stihl recomends mid range gas
go to your stihl dealer purchase a bottle of STIHL DE-CARBONIZER if they dont have it have them order it for you.
never pump water in a 4mix
Never EyE Ball the oil when mixing gas
use stihl oil mix only

Stillwater
11-24-2007, 11:38 AM
Me I just run super, I do not know these problems unless it's running too rich?
A lot of that black soot is as likely petrol contamination, both dirt buildup from petrol contamination and soot looks black.
True soot is made of carbon, that comes from running too rich, a dirty air filter would contribute as one example.

Several tank fulls of a pure acetone mixed in with fuel might do it, 3 ounces acetone per 10 gallons fuel.

petrol?

You from the UK.?

Stillwater
11-24-2007, 11:42 AM
anyone intrested in decarbonizeing stihl products needs to go to this web address

http://hastingsacehardware.com/Dan/Stihl%2520Engine%2520De-Carbonizer.pdf

yungman
11-24-2007, 07:01 PM
That is the reason I am leaning towards Honda or Makita or Robin 4 cycle trimmer that have separate oil and gas. I can just squart water through the carb using a squart bottle and run the egine by trimming the lawn to get rid of all the water. Then change the oil to make sure all water is gone.

Anyone have opinion or the Honda HHT35 35cc 4 cycle, Makita 24.5cc 4 cycle? I heard it is even more reliable than Stihl!

I am running for cover!!!!!

Thanks

Stillwater
11-24-2007, 08:12 PM
your leaning toward makita robin and honda 2/4cycle so you can clean and decarbon with water? please tell me you have more reasons. Becouse reliability is not one of them

MOW PRO LAWN SERVICE
11-24-2007, 08:18 PM
HONDA,not reliable?

yungman
11-25-2007, 01:15 AM
Do you mean both Makita and Honda 4 cycle trimmers are not reliable? It is just easier to use water to decarbon if it has a separate oil and gas, that's not the main reason. But not reliable is the big thing. I heard good things of them and I heard very mixed review on Stihl 4 Mix. Maybe I should reconsider Shindaiwa.
Thanks

yardmanlee
11-25-2007, 08:35 AM
anyone use the stihl ultra hp syn oil mix ? I ran it this yr. in all my 2 cycles stihl stuff and had to replace a muffler on one fs 80's and my older back pack blower and one of my hand helds, not saying that could be the cause, but was wondering if anyone else had the same problems ? and yes I did clean the spark arrestor screens and the mufflers were still stopped up !!

Stillwater
11-25-2007, 10:38 AM
HONDA,not reliable?

we are talking about 2 cycle engines vs/ stihl 4mix engines
I was not saying honda 4 cycle engines were not reliable that would be just ******ed to say that.

Stillwater
11-25-2007, 10:57 AM
Do you mean both Makita and Honda 4 cycle trimmers are not reliable? It is just easier to use water to decarbon if it has a separate oil and gas, that's not the main reason. But not reliable is the big thing. I heard good things of them and I heard very mixed review on Stihl 4 Mix. Maybe I should reconsider Shindaiwa.
Thanks

you can find mixed reviews on every product made on this planet it is not hard. Been in business a long time and used many different brands of gas tools. Now when it comes to money. My years of documentation reflects that stihl has been the money maker for me. They work and are rarely worked on. Dont miss understand me I have had problems before but overall my records show Stihl has by far been what keeps me running and cost me by far the less in down time, I have records that tell me this and it would be stupid of me to ingnore them. Keep a open mind and buy what you like and can afford I am sorry if I implied makita and honda are not reliable that statement is clearly not true.

yungman
11-25-2007, 02:54 PM
Thanks Eshskis
Thanks for clearing up. You use mostly Stihl, are they 4 Mix? I know the older Stihl are very good, it is the FS110 and FS130 I am interested. If they are good then I would definity consider it also. I read up the De-Carbon stuff you post, it is not too bad to use.
Again thanks for your info.

HenryB
11-25-2007, 03:00 PM
fs100rx is the only Stihl trimmer to choose. Trust me, I've owned all of them. My 4mixes have given me zero problems.

yungman
11-25-2007, 07:35 PM
Hi HenryB
You mean including FS110 and FS130?
BTW what oil you use and what ratio?