Do you still use leaded fuel down under? Unleaded builds carbon much slower then the old days of leaded fuel so your frequency of cleaning can be stretched over older times. Even then, 100 to 300 hours is for flatheads and they are EZ to remove and clean. Just replace the head gasket at all times.

OHV engines burn so much cleaner the interval is 500 hours or more and few home users put that many hours on a mower before they've otherwise run it into the ground.

Hi Nevada Walrus
Merry Christmas and Happy New year.
I am using unleaded gas 91 octane from Chevron. Flatheads? Is this the ordinary kind in the regular mower where the valves are up side down on the side of the engine instead of on top of the piston? This is the kind I have. It is only 5 months old Troy Bilt TB836 consummer mower only. I just read the operating manuel and saw that.
Does spraying water really decarbon the valve like the cars?

My new Honda trimmer is a OHV so I don't have to worry about it?

Thanks

Sorry bout the down under thing. For some reason i was thinking you were one of our
aussie friends.

Your mower engine is apparently a flat head as i call them. The industry general refers to them as eithe L-Heads or side valve engines. The valve are along side the piston, your new trimmer has the valve in the head or OHV.

I wouldn't worry about the trimmer, ever. Had you gone with the stihl or other mix fuel 4 strokes then It would a possible need.

Your mower engine is real easy to remove the head to clean. Will water work, I think it would but it would need to be a fine mist and probably take a lot longer then you want to fool with it. Probably remove the head and clean it a lot faster.

Even then, I would wait til at least getting to the 300 hour point before worrying about it. In my opinion having some carbon build up is a good thing. As long as its not so much that the piston start hitting the head the build up raises compression, more power!

Decarboning a Old lawn mower Flat head engine is very easy and it will run better after you decarbonize it. I got lawn mowers out of the trash and all they needed was cleaned up this included the comb. chamber. Cause the owner didn't know how or cared to take care of it, after a few years it wouldn't start so it got trashed. they are everywhere. especially in the spring when they try to start them after winter storage.

Very simple procedure, you remove the head. use a wire brush or rotary brush on a drill and remove the carbon and maybe a screwdriver or putty knife for the hard pieces.

You want to do this with the piston up and the valves closed. after you remove all the carbon you see take some carb cleaner and wash every thing out and off. run the piston down the bore and wipe out any residue. spray and clean around the valves and clean the head gasket up and reuse it. don't worry I used the head gasket over on my tiller engine for 38 years and I've decarbonized it maybe 4 times. I have never had to by any gaskets for it and I also have cleaned out the carb. many times. Clean you plug, install the head and torque starting from the inside out gradual till you reach you final torque. Or just tighten them up good and snug if you know how tight things should be if you don't have a torque wrench.

Small gas engines only need decarbonized when preformance starts to go south. You still need to check tightness on every nut and bolt occassionally IMO This includes the head bolts. there going to be some guys that says it's not needed or they never done that, but that don't mean it's not needed if you plan on keeping equipment running a very long time.

The more pre-ventive maintenance is done the less decarbonizing internals are required. meaning the cleaner you keep your engine running the less it will carbon up. All about clean filters, gas, gas tanks, oil, and spark plug. Neglected small gas engines die a early horrible death, well maintained ones run for almost ever!. JMO most will disagree

rcmoser, Newer engines use a different head gasket, have now for maybe ten years. They no longer have any asbestos in them and the new make up will always stick and tear apart when removing the head. Well, they will once ran one time and brought up to full temp.

You're right about the old style gaskets, if they weren't overheated or used with loose head bolts they often could be re-used, but not anymore.

Thanks for all the info. That make me feel a lot better.

BTW I have the Shindaiwa C4 blower, Is that more prone to carbon buildup problem. That one is going to be hard to remove the head and clean because it is a OHV. Would that be pushing it to spray water into the carb being mix oil and gas? Using a spray bottle that spray a mist into the carb?
Thanks

On that one pick up a bottle of decarbonizer fluid from a Stihl dealer. This stuff works good if you do it regularly. I would say once a year for your home use. If you let it go and the carbon turns hard it won't help much.

Bring piston up to TDC with valve in that overlap between exhaust and intake. That way they are both slightly open. You'll need to remove the valve cover to verify.

Then fill the combustion chamber with the fluid and let set for 12 hours. Set level so fluid doesn't run out. With valves left in the partial open position you will clean the seating areas of the valves and seats as well.

Don't leave set more then 12 hours, this stuff is an acid and will begin to damage the metal if left much longer. Dump the fluid out in the sink with water running to dilute. Fill the cylinder back up with mix fuel and dump in used oil container. Aim plug hole in safe direction and crank on it until it quits spitting. Make sure ignition is turned off when spitting out the fuel.

Then put plug in and try starting with no choke.

Thanks for you advice, I'll look for the decarbonizer.

Personally, I never bother with decarbonizing any 4 stroke. I've not seen one in decent operating condition that required it.
If it runs good, leave it alone.

From all the input so far, except the Shindi C4, all the other stuff is fine. Lesson learn is stay away from C4 4Mix next time, either buy 2 cycle or 4 cycle with separate oil and OHV.

I should have come to the forum to learn before buying anything. Went out and bought the top of the line Troy Bilt mower thinking that's the best!!! My next hedge trimmer is going to be 2 cycle and my next mower is going to be a Honda because it's an OHV. well, at least I bought one right....Honda HhT31S trimmer. Absolutely love it!!!

Maybe this will give me a good excuse to buy new toys down the road!!!! Tell my big bose( wife) " Sweety, my mower and my blower is coughing out carbon!!!!"

Happy New Year to you all

Hope they keep the 2 cycle around for a while!!

Yungman, I'm surprised that nobody mentioned Sea-Foam yet. It's great for carbon removal as well as prevention. The spray version is called Deep Creep. Check out their site. Link below.

Here is a link that might be useful: Seafoam

Where do you find this seafoam, I looked at my normal retail stores I shop. Dollar store, Hee, Hee. and haven't seen it. If it does half of what is says my decarbonizing days are over!!?? ZMAX claims the same thing anybody tried it???

bill if you keep good care of you equipment you may have to never decarbonize it. Most don't, they never change the oil or air filters. Run the equipment low on oil, and never clean the spark plug. after a few years of abuse the won't start and alot get trashed. This is where I find the gold. Anything free that works is good to me. Normally I just have to clean them up internally and externally.

With all the recent Ice storm damage I picked up a couple of chain saws out on the curb. One with a 20" bar. Cleaned the engines up and they run real good, may need a new bar and chain do to lack of pre-ventive maintance. Guess what was wrong with them Carboned up and the spark plug fouled.

Yungman,
Nothing beats a head removal and inspection every 100 hours or so. I wait until something happens like a gunked up spark plug before I remove the head.
Carbon tends to form from oil burning and you should be able to tell from the smoke if an engine needs rings and a subsequent head cleaning.
I doubt any of your engines need premium fuel, they just do not have the compression needed for the hotter octane.
You have some interesting questions.

Seafoam does work.I get mine at Fleet-Farm.Add to gas in my mowers,snowblower and auto.They also make it for transmissions.Had a 94 Dodge van than had a sluggish shifting trans.Garage said it needed replacing.Added a can of Trans. Seafoam and shifts like new.Saved me the cost of a trans.

Well, I went out and bought the Sea-Foam already. Question is whether use it as gas treatment everytime starting now or this it as treatment ones every few months?

Hey Navada Walrus ( Bob). You have any comment before I put it in the gas? I respect your opinion.

Do I need to use any more fuel stabilize like Stabil?