*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Random Quote: I fish better with a lit cigar; some people fish better with talent.
May sound dumb...but this comes up a lot and I have no idea what you guys are talking about. When someone says "they decarb every 6 mo or once a year" or whatever...what procedure are they doing? Greg
Greg,
Decarbing is the act of getting excess carbon out of your 2 cycle engine. Too much of it can kill your engine (Blown Head, Piston scarring, etc). There are several ways to decarb. One way is to run a concentrated mixure through your fuel system of something like Sea Foam (available at Napa, Carquest and other auto stores.) another way is to buy Mercury, Yamaha, or Evinrude spray and spray it into your carborated engine through the air inlets. Some decarb every 50 to 100 hours I do mine about once a year since I use good quality oils and an additive like Ring free that helps reduce carbon build up in my engine.
Sure today there is all kinds of products on the market for de-carboning an engine; I'm old school, I use water.
It is a lot easier to show one how to use water than it would be to explain. But let my words ring clear, using water one can easily creat bent valves, rap valves off of the tops of pistons, bend rods, pop a holes in the top of pistons, blow heads off of the block and even send pistons through the block wall if done incorrectly. But despite the dangers, I have and will always continue to use good old H2o.
Substantial build up of carbon in any engine is a reason for concern. It is just part of my engine maintainance program and it should be everyones as well.
This works for Carbed, EFI, Ficht, HPDI, Optimax and even 4 strokes...
First you need a separate small fuel tank. One of those 3 gal red Tempos works great or an empty gal mike jug will also work, but might be a bit messier..
I use Seafoam over the OEM stuff like OMC Engine Tuner or Merc Power Tune because in the last few years they changed the formula and you have to let them sit up 12 hours. Who's got time for that?? Seafoam you can buy from NAPA, CarQuest or other auto stores. Seafoam works in 15 mins.
You'll need 3/4 gal of gasoline and one 16oz can of seafoam for each engine. Don't forget to add 3oz of oil if you are premixing in a carbed engine. Use about 3 ft piece of fuel hose off the little tank. You connect this tank to your engine by pulling off the main tank fuel hose off the intake side of your water separating fuel filter and plug the hose off the small tank on to that fitting. Or you can separate the fuel line on the tank side primer ball, so you can still use your primer. If you have an engine that has fuel plug then you need a fuel plug on the little tanks hose.
Start the engine, let it warm up and start pulling the mix into the engine. You may have to increase the idle to keep it running once she get loaded with the Seafoam. Run the engine 15 mins in the dock or just cruising around under 2500. Then shut it down and let it sit for 15 mins. Restart the engine, the smoke you see is the carbon burning off. Do the whole thing again and let her sit again for 15 mins. If she smokes after the second time do it again, but I've never seen one still smoke after three doses. The gallon mix should be enough to do this 3 times. You don't need any wide open throttle, you don't need to change the plugs. If it's cleaning the combustion chambers it's also cleaning the plugs, but every 50-60hrs is good time to change plugs in most engines.
I cleaned a antique evinrude one time that had a 1/4" of solid carbon on the exhaust chamber walls by running a 1/2 gal of the mix through it. Seafoam has been around since the 30's and it's what they used when they were burning straight 4 stroke 40SAE oils in outboards.
You guys with the 4 strokes think you are immune from this? Those engines work 10 times as hard as any auto engine ever will and they will carbon up. I bought a Bronco two years ago that had 95,000 miles on it. When I used seafoam on it I had the neighbors hanging out of their front doors looking for where the fire was after I started it the first time there so much smoke.
Too many are under the assumption that it's totally the 2 stroke oil that causes the carbon, Wrong... it's also the additives they put in the fuels today. The carbon inhibitors in 2 stroke oil are there for this reason also. Remember when gasoline used to smell like gasoline, today it smells more like bad cologne.
For those guys that like to do the carbon treatment by spraying it down the carbs Seafoam also comes in spray can called Deep Creep. It's the same stuff under pressure. Says right on the can Oxygen Sensor Safe, for you Yam guys.
After that if your engine maunf recommends a daily additive treatment then do that in the mean time, but all 2 stroke outboard need decarboned every 50-60hrs. If I owned a 4 stroke I would do it the same. Once you are set up with the tank and hose the Seafoam is only 5-6 bucks can. It to easy not to do it.
Decarbing is the act of RUINING yoru motor. Leave it alone already. Add Ringfree as suggested to each tank of gas, use Yamalube oil, and enjoy the long life of your motor.
Ever notice the Yamaha manual DOES NOT state to decarb your motor? There's a good reason for that. Cause ya shouldn't. You do more damage to the motor than good.
Birdman..interesting twist on the topic....this is my first Yamaha after many years of Johnsons....have never decarbed anything to this point and got many hours out of the Johnsons. After reading the board, though, it seemed like something I really should be doing. I may still decarb...who knows. I'll have to read/research some more. Greg
I now have a evinrude 150 FICHT but previously I had a 1989 Yami 200. I never ever decarbed it once in 14 years. The engine has over 1000 hours on it and still runs like it was out of the box. Also it was run on Wal-Mart oil. While I don't run my ficht on anything but the Ficht oil and I do add all the additives I often wonder.... If I had a regualar two stroke I certainly would not decarb her.
Here's some of the skibbes on why someone should decarb.
Carbon adds weight to valves and pistons. That weight reduces response time of the engine. That weight reduces efficence of the engine.
Carbon reduces Horse Power.
Carbon reduces air flow.
Carbon build up is know to cause engine knock and run on.
Carbon build up can give you hot spots. Hot spots on piston tops will give the piston a lean to it, this causes the piston to wear one side of the cyclinder more than the oposite side - in effect, making the bore out of round, oblong if you will. Hot spots have been know to blow holes in tops of pistons.[/list]
How what the the benefits of not decarbing?
quote:Originally posted by Birdman: Decarbing is the act of RUINING your motor.
I respectfully, but unequivocally, disagree with that statement.
That said however, I wish no ill will towards the poster, their opinion, nor to their OB, yet I will advise any and all new OB owners to do otherwise.
FWIW this topic - decarbing - has been rehashed many times, check the archives. Truth is, there may be many factors why or why not your specific OB may build-up carbon or it doesn't. These can be your use, duty cycle, interior finish of cast surfaces, porting/jetting, quality of fuel, quality of oil, etc., etc., . Heck, one could run twin OBs and have one load up while the other runs great as is. So the point is ... wouldn't one want to know and possibly prevent a catastrophic incident from occuring ?
For the record, many OEM manuals emphatically state that the OB should be decarbed periodically. I don't know whom Birdy might be quoting, but for me ... I'll go along with the OEM manufacturer's word, plus the opines of Dunk, Seahorse, Sal, and other OB gurus.
Truth is ... your OB needs carbon (cools the rings) ... but not too much. FWIW my brothers and I do the "Dunk" Seafoam treatment, every 50-60 hours, for up to 11 or so OBs that we run each season and we have NEVER had one problem. I've logged 22+ years (running when sold) on OMC engines ... you?
My brother's in law's chainsaw stopped working this Fall, so I emptied the gas tank, added Seafoam and removed the plug wire. Primed it and cranked it through many times, then let it sit overnight. Nest day, we drained the Seafoam and filled up with new oil/gas mix. Started 1st pull ... and hasn't burped once yet.
Seafoam - IMHO cheaper and better than the rest, period. Use Ring-Free, OMC Carbon Guard, or the equivalent if you choose to spend more $4 than you need to . If one chooses to use nothing, that's cool too .
Like many things in boating ... your mileage may vary ...
I agree with Real Rascal.Decarbizing(?) will definitely help longevity of an outboard.Products like Engine Tuner(omc),Power Tune(merc) is definitely a help.I don't have the answer on the direct injection engines because of the nature of their oiling systems.Oils ,like Quicksilver/Mercury precision Premium Plus has a additive similar to Quickleen(which is Mercury's version of Carbon Guard or Ring free).Three things that can kill an outboard is poor quality of oil(carbon build up),fuel quality(ie alcohol),& improper propeller.
I would like to add to my list above.
Carbon can restrict the movement of the rings.
* decrease in compression
* piston slap
* scoring of cyclinder walls
* uneven wear to cyclinder walls
Premature engine failure.[/list]
Merry Christmas to All
Reel Rascal,
To QUOTE YAMAHA, "DO NOT DECARB your Yamaha outboard motor". Quote un-quote. Right from the Yamaha mechanics school.
The reasons (to answer garett's question):
* You ruin and nulify about 6 different sensors including but not limited to the O2 sensor. The sensor's are damaged by two things: The chemical treatment, and the residue left behind that ends up stuck in them.
Remember, if you spray, add, drip, plop or use any other means to put something into your motor, it then has to drip, plop, squirt, or even burn (creating you guessed it, chunks of CARBON) to get out of your motor.
Agian, THIS is the reason Yamaha recomends using Ringfree (a Decarboning agent) in every tankfull of gas. This way your not allowing carbon to build up in the first place.
I run a Yam 200 HPDI. I decarb using Sea Foam every 50 hours and use Ring Free. Even with RF, I have carbon build up that Sea Foam removes. Use the pup tank, works great and it is easy. Engine runs great.
What if your motors are fouling plugs and blowing out a lot of blue smoke despite using Ring Free and Yamalube. Should one decarb under those circumstances?
How do you "decarb" your 2 stroke?? 
Boston Whaler, "MUMBLER", 24' Outrage, twin 175 HP Evinrude Ocean Pros. 
Snowball, the cat... 
?
... and hasn't burped once yet.
. If one chooses to use nothing, that's cool too 
"Life's too short to own an ugly boat ..."
