Carbon Buildup

JeffSlade

Seaman Apprentice
Joined
Mar 28, 2001
Messages
43
I pulled the plugs out of my 75hp Force yesterday and upon inspection inside the cylinders noticed quite a bit of black flaky buildup on top of the pistons. I don't have a boat shop within 30 miles and wondered what I could do to clean it up. If I can get it cleaned up what should I expect in performance improvement if any?
 

rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: Carbon Buildup

YOu need to de-carbonize your engine. This is something that should be done at least once a season. Here is a link to a product you can get for a one time treatment. There is also a gas additive that help to reduce carbon buildup and sticky rings .<br /><br />If anything, this could restore HP and help keep you engine running healthy.<br /> http://www.boatfix.com/bykeyword.ASP?keyword=de-carb
 

JeffSlade

Seaman Apprentice
Joined
Mar 28, 2001
Messages
43
Re: Carbon Buildup

Thanks, I'll give it a shot.
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ODDD1

Lieutenant Junior Grade
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Jan 23, 2001
Messages
1,054
Re: Carbon Buildup

Jeff, dont do anything...carbon buildup on pistons is NORMAL.....attempting to clean it out will have no effect on performance or longevity.....most products marketed to 'remove' carbon also do a fine job removing the binders/adhesives that hold the gaskets togther in your motor!<br />Dont get me wrong..there are places inside your motor [the rings/ring lands] that carbon becomes a problem, but after it builds to a point of affecting engine performance 'snake oils' will not help. some people feel 'decarbing' as a regular maintenance is normal an healthy.....I feel it just hastens other failures in the engine...use of good oil and decent fuel will accomplish the same thing.
 

JeffSlade

Seaman Apprentice
Joined
Mar 28, 2001
Messages
43
Re: Carbon Buildup

Does anyone else have an opinion about this? I have read many posts about decarbonizing and I guess I am just confused. I understand your point ODDD1 but don't understand why a product would destroy parts it is "supposed" to be good for. 12Footer is always talking about fogging his Force twice a year, do you have to de-carbonize too? Let's talk about this. Thanks
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rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: Carbon Buildup

This is the first anti-decarb opinion I have heard. And after reading some of your other posts, ODDD1, I tend to put your opinions on par with some of the pro-decarb people I have conversed with.<br /><br />As I understand it, the Force motors burn very cool and are susceptable to excessive carbon buildup, especially with prolonged periods at idle or trolling. (truth or not?) <br /><br />I am no expert, obviously, but the preponderance of opinions say this can lead to sticky rings, predetonation, and inefficient burning of the fuel. If this is indeed the case, are we talking about a lesser of two evils? and which is the lessor?<br /><br />I am very interested in your opinion.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Carbon Buildup

Oddd1 has a point. The only product I have enough experience with is the OMC Engine Tuner. It is very powerful. Most people put it in and figure if letting it set for 4 hours is good then letting it set a week is better. It will actually dry out the cylinder walls, that leads to piston scuffing and.....well you know the rest of the story.<br /><br />If your combustion temps are correct you shouldn't get coking or stuck rings to start with. If the motor is capeable of max RPM's, you use the correct (fresh) octane fuel with the right plugs the combustion temps will be correct no matter what RPM you cruise at.
 

JeffSlade

Seaman Apprentice
Joined
Mar 28, 2001
Messages
43
Re: Carbon Buildup

So what should I do? I am led to believe each side. If I do de-carbonize, it might thrash my engine, if I don't my engine might thrash anyway. I use the best oil I can find and am still up in the air (as the rest of us are) about which octane gas to use in it. I believe in taking care of all of my "toys" but sometimes we all get lazy and don't do what is necessary. I just don't want to make any mistakes. There is a lot to understand in this racket and I'll be learning for a while. I appreciate everyones input and really enjoy this board. If anyone can be of further help on this subject I would be grateful. Thanks again.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Carbon Buildup

Ahoy, Jeff. You are not likely to make a mistake if you take your advice from ODDD1 and/or Dhadley. Leave it alone.<br /><br />Bon Voyage,<br />JB
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JeffSlade

Seaman Apprentice
Joined
Mar 28, 2001
Messages
43
Re: Carbon Buildup

Thanks JB, I will take your advice and leave it alone. What about carburetor cleaners, or foggers? Should I use them? Again, thanks for your help. JeffSlade
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Carbon Buildup

The bottom line is -- if you choose to decarbon BE CAREFUL. Don't let it sit in there too long. Run the motor long enough under a load to get all of the chemical out. And you will most likely need a new set of plugs when you are done.<br /><br />Good luck!
 

ODDD1

Lieutenant Junior Grade
Joined
Jan 23, 2001
Messages
1,054
Re: Carbon Buildup

Roger all I can speak from is experience...i have repaired/been rebuilding chrysler/force/sportjet/Ldrive motors since force took over in 1984. I have done literally hundreds myself and consider myself a fair judge of what kills these motors....yes these motors make alot of carbon..compared to loop charged engines,crossflow motors are dirty. the tops of pistons in a crossflow motor will always carbon up, this is not a bad thing..carbon is a heat insulator, it will help hold heat up in the combustion chamber, were it belongs....carbon on the sides by the ring grooves [specially in the grooves] is the problem, too much and the rings stick and dont contact the cylinder walls.bad things happen I have seen many people attempt to decoke stuck rings with little success..you end up rebuilding....the only motors i have seen that have excessive carbon also show other signs of using low grade lubricants.....so does decarbing a motor help? as maintenance not any more than using good fuel/oil. if the motor already shows signs of carbon damage[stuck rings] like loss of performance will decarb bring the motor back? no, once you notice a performance drop it is usually to late. I guess that all in all i cannot say they are a bad product but i have found little use for them...most people that attempt their use usually expect to much from them.
 

Frank

Cadet
Joined
Apr 9, 2001
Messages
14
Re: Carbon Buildup

Mercury service manual for the 225 EFI says to de-carb every 100 hours.
 

12Footer

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

Speaking of mercs, I have a 25 year old merc that gets de-carbed twice every year, (at<br />least for the 5 years I have owned it). My others do also,but i haven't had them as long.<br />I have never had, nor have I heard of problems resulting from de-carbing an outboard. I also put my weedeaters up for winter flodded to the gills with the stuff.<br />I have never had to throw away a plugged muffler as a result,and they are reliable.<br />I don't mean to confuse the subject, but I do swear by the practice, especially those folks up north who must store their boats when the water gets too hard to float in.<br />My .02
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12Footer

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

I forgot, I want to agree with ODDD1 on a point or two...Additives in outbaords is not<br />adviseable, as it messes with the octane, and will put alcohol-inriched fuel TO SHAME at eating the fuel pump and other plastic or rubber parts.<br />These additives can also foul plugs on their own,without any influence from carbon.
 

Bluefish

Petty Officer 2nd Class
Joined
Mar 14, 2001
Messages
125
Re: Carbon Buildup

I just wanted to put my two cents in,I have been runing valvtect carbon free ( gas additive ) in my outboard for 10 yrs and about 3 yrs ago had to do a head gasket and fond the pistons and walls nice and clean.And 12footer I was wondering about what you said about additives messing with the octane....We have marine fuel up in NY with the valvtect added selling at the fuel station. ??????<br /><br /><br />.
 

bobmoore

Petty Officer 2nd Class
Joined
Mar 25, 2001
Messages
109
Re: Carbon Buildup

wow after reading this i wander if i have a problem with my 1990 120 force l-drive ,when i pulled the head and exhaust manifolds off last week i had on carbon what so ever anywhere,around the pistons or liners,could my engine be running to cool. i did have to change the theromsat,it was stuck open.what do you all thinki hardly ever run at full throttle, i run it around 4300 to 4800 rpm,s at 34mph,s and compression on the engine is at or around 132 to 138.thanks
 

rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: Carbon Buildup

Looks like the jury is out.. I live in a northern climate where we have the fall mothballing sequence we must go through. At the end of the season, I decarb, do the lower unit lube, fog the cylinders, and stabilize the gas. In the spring I burn out the fog and replace the plugs, then hit the lake. <br /><br />My opinion is that a clean engine runs better than a dirty one. I follow the instructions on the can, which specify leaving the agent sit for 20 miniutes or so and then running it out. I don't expect radical performance gains by doing this, I do expect to extend the life of the motor and the trouble free operation.<br /><br />My father had a 5hp Sea king that never had the lu lube changed, never fogged it, never decarbed it, never cleaned the carbs, etc.. This motor died a well used old motor.<br /><br />I'm not feeling quite as lucky as him..
 

12Footer

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

Bluefish, to answer your question about additives adding octane,let me elaborate..<br />I have one engine (Force 50HP), that wont even run with decarb or sta-bill additives.<br />I tried using the ValTect at half the recommended dosage, and it runs fine. I have,however, had a plug foul.<br />Any time we add anything to fuel,whether it's Sta-Bil or mineral spirits, it raises the octane level of the fuel. Off-the-shelf octane boosters are little more than mineral spirits in an expensive bottle.<br />Rule of thumb is, the higher the octane, the less explosive the fuel is.<br />BobMoore, I don't think it was running too cool because the cylinders were clean.<br />But it did run too cool if the t-stat stuck open. I would be more concerned that maybee spotless cylinders would indicate too little oil in the mix,or a lean-burning condition from fuel starvation. That can destroy an engine faster than heat.<br />Like ODDD1 said tho,(loosely qouted here) "carbon in itself is not detrimental if it is controlled. The problems come-in from cheap fuel".....<br />I will add to this tho, that too much carbon fouls plugs, sticks rings in their pistons, plugs muffler-equipped 2 cycle engines, and gums-up reeds. <br />It can also get so bad, that additives or fogging can't make a dent in the stuff.
 

yasefue

Cadet
Joined
May 22, 2001
Messages
7
Re: Carbon Buildup

try a product called Bi-Tron; mix 2 ounces with your oil. Run 2x6gallons and thank me later. It is a Canandian product manufactured by NATO International; Vancouver, B.C.,(advanced molecular engineering product) I run a 65 year old outboard and since using this stuff she runs better than new
 
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