Carbon Buildup

Dunk

Petty Officer 2nd Class
Joined
Feb 11, 2001
Messages
127
Re: Carbon Buildup

I couldn't disagree more with ODDD1 or Hadley. First OMC's Engine Tuner tells you right on the can to leave it sit for 12 hrs. It used to be 30 mins then 4hr but now they've changed the formula again and recommend 12hr. Seafoam is the best and the fastest(5-15minutes). NAPA and CarQuest carry's it. I've seen 100's of 2 stroke engines seize up from carbon. What happens is the ring lands(grooves) pack up with carbon. When this happenes they can't disapate heat, they swell up and grab the cylinder walls. It either siezes the engine or the rings break and the piston trips over the rings destroying the combustion chamber.<br /><br /> I have several Evinrudes from the late 40's. A 22.5hp Speeditwin and a 50hp Big Four. They were made to run on 16 to 1 mix of straight 40wt motor oil. You want to talk about carbon, you aint seen nothing like the carbon that was in those engines when I bought them. Both were in the 80lb range for compression. Once I got them running one treatment with Seafom removed the carbon and both have compression in the 130-140lb range, so saying a decarbon won't bring them back is wrong. I've run both of these engine over 200hr since without problem. I use Seafoam in them every 25-30 hrs even with OMC TCW3 oil. I've run OMC V4's and V6's to 2500-3000hr without problems because I treat them every 50 hrs with a decarb. All two stroke engines need to be decarboned.<br /><br /> Seafoam is nothing but a mineral sprit concoction that soaks into and allows the carbon to be burned out of the combustion chamber. The smoke you'll see after you restart the engine will prove this to you. Deep Creep is the same stuff in a spray can. This stuff has been around for over 50 years and learned about it from the old outboard guys.<br /><br /> You spray it down the carb throats while the engine is idling. Once you have 10-12oz sprayed in you drop back the idle spray hard enough to drown/choke out the engine with the stuff and stall it. Let sit for 15 minute and restart the engine. You won't believe the smoke.<br /><br /> The problem is not with the oils you are burning it's all the additives in the fuels that the outboard maunf's have been chasing with their new oils. OMC, Merc and Yam oil contain twice the carbon inhibitors as the cheaper oils(Wally World, Texaco, etc.)
 

SeaBear

Seaman
Joined
May 24, 2001
Messages
53
Re: Carbon Buildup

I hesitate, as a new member, to join this discussion but there are good points on both sides of the argument. Be careful what you stick in your engine is good advice. I have found in the past in my 2-stroke motorcycling days that decoking gains you at least another 2-3 mph [hardly worth it] - if you realy want to do it properly then get the head off, etc and do it? However, I am passing on a 'tip' my college lecturer told me when I was doing a motor vehicle technology course 20-odd years ago and I know this will cause some tremors but I am only the messenger here? 'Dribble' or spray water [yes good old H2O] into the air intake while running at about 1500 rpm [fast idle] for about a minute and the extra oxygen will cause the excess carbon to burn up? Most people I tell this to wince and give me 'those' looks but there was a time when engines were steam injected for extra power?
 

sony2001

Chief Petty Officer
Joined
Mar 17, 2001
Messages
607
Re: Carbon Buildup

Yes SeaBear, I also heard of it 20 years ago from the son of a chemical engineer to one of the oil com****** nearby.<br /><br />------------------
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: Carbon Buildup

Seabar, don't hestitate to join the topic...<br />And it ain't an argument, it be a "DEBATE"
smile.gif
<br />SO THAT'S WHY MY DAD DID THAT!!! I am approaching the big-50. But I have vivid memories of my dad,dippin his hand in the<br />lake,and dribbling water into the half-throttled engine before loading the boat.<br />He claimed he "was giving the engine one last drink"....Did it every time...I never<br />got an answer why. He probably knew I was too<br />young to understand, so he told me what I<br />wanted to hear.
 

frankp

Recruit
Joined
Jul 22, 2001
Messages
4
Re: Carbon Buildup

Hi guys,<br />This brings back memories. My uncle used to do this "dribbling" of water into a car carb, pulling the throttle to keep up the RPMs so the engine wouldn't die. Lots of smoke (steam I think). Sometimes he would use kerosene, or a mixture of kerosene and water. He called it an "Oklahoma tuneup".<br />Said mainly, the cool water shrank the carbon into loosened flakes on the piston heads, and more importantly, the valves.<br />Anyway, it seemed to run better afterwards.<br /><br />Frank
 

dmessy

Chief Petty Officer
Joined
Jul 8, 2001
Messages
505
Re: Carbon Buildup

I'm in the process of rebuilding my 75 HP Force due to carbon sticking the rings in all 3 cylinders. The top one ceased first.It's a 1996 and I just got it from a owner which I believe ran crudy gas, old gas , and probably never measered the amount of oil he put in. <br />I guarantee I'll be decarbonising my rebuilt motor yearly with Quicksilver Power Tune or equivelant. I wouldn't recommend fuel additives. I suggest you check your compression on all 3 cylinders before you do anything.
 

mbb

Petty Officer 2nd Class
Joined
Apr 20, 2001
Messages
176
Re: Carbon Buildup

Even on the automotive sites they talk about decarbing by spraying water into the intake as a way to help pass emission tests. apparently the carbon holds heat and leads to preignition and more emissions. My personal automotive experience with carbon on my 89 toyota v6 4wd was that my milage dropped off from 20 to 15 mpg by time I reached 175,000 miles. took it to dealer, cleaned injectors, etc, no change. Ran ONE treatment of B12 Chemtool thru on 1 tank of gas and I was getting 19 mpg again, and I hadent seen milage like that in 4 yrs or so.<br /><br />I decarb my outboards now at least once per yr, never had one fail. But I had a 79 evinrude 100 w/over 2000 hrs that was never decarbed, it never failed either. My Understanding is that manufacturers reccomend it today on the higher performance engines made due to closer tolerance and fuel additives that make more carbon. If they produce and sell their own engine tuner products, it cant be very harmful to an engine when done properly.
 

seaman

Cadet
Joined
Jul 27, 2001
Messages
25
Re: Carbon Buildup

ok every one agrees no additives so do I decarb chemical yes if flushed within a few hours fog motor specially up north essential salt water replace water pump yearly if the decarb dont work you can always take it apart and thoroughly clean and replace a few a those parts you were worrying about. So now we are down to where we know we will have carbon build up after we just cleaned the motor of carbon doers any one know how regular that de carb should be done or that it would be ok maybe every 3 months of use .which reminds me the more ya use that motor the better off it will be
 

rich-flanders18

Recruit
Joined
Sep 11, 2008
Messages
4
Re: Carbon Buildup

Everyone seems to be having a bit of a bun fight over this whole de-carb chemical treatment and fuel additives. Here is a test my friend i did with his dads motorbike workshop and an Aprilia RS250cc 2stroke motorbike. Ok, so the bike has over 21k miles on the clock and a bit rough around the edges, could do with a tune and service but here we go. DYNO TIME!!
-Bike on the dyno, no mods as we found it when we came in that morning, quick run round the block to warm her up. best of 3 runs got us 53hp.
-Bike on dyno after a an extremely smokey decarb and blast up and down the road 5 times. best of 3 runs got us 57hp.
-bike now run with a bottle of nitrox fuel treatment octane booster added to the fuel in the tank. supposed to give you more power. quick run round the block to get it in the carbs. best of 3 dynos 55hp.
-bike fuel tank drained of the "performance" additive. filled with premium fuel highest octane available from station. best of 3 runs 57hp HOWEVER power across the range was much higher than standard fuel after the de-coke and air fuel ratio was smoother compared to the heart rate monitor we got before!

Just an example of these products.

I de-coke once a season, run on premium fuel and premium 2 stroke oil. We all make our own choices in life.
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: Carbon Buildup

Frank P.

I used to use a water/methanol mixture when I cleaned the carbon from my 327's and 383's in the sixties. In those days we used a 60/40 water/meth mixtures in our round aircraft engines to give us more power at takeoff. It kept those engines clean and it kept my auto engines clean also.

ET AL

As for decarbing, I have been doing it for about 45 years and don't intend to stop now. I have decarbed and fogged two stroke and four stroke, motorcycle engines, aircraft engines, auto engines and boat engines. I have not seen any, repeat any, indication of it harming these engines. BTW, I have maintained, overhauled and operated all of the above. ;)

While I agree that carbon can be a good insulator in certain applications, it is not something that you want inside a reciprocating engine. :eek: Carbon on the cylinder head/valves/piston creates hot spots that lead to detonation and preignition. Thick enough, it causes increased compression which leads to detonation. When it blocks oil scavange holes it causes overheating and component failure. When it builds up in ring grooves it causes excess friction and component failure. :(

A safe effective method of carbon removal is the seafoam process that is captured as a sticky at the begining of this forum. :) You don't have to be an aeronautical engineer to use it and it works well. Additionally, I do the same thing to my lawnmower, edger, string trimmer, blower etc and they all live long lives and give good service.


Thaaaats all folks!

John
 
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