Decarb Dunks Method

[jwall116]

I know I read what I am about to say in one of dunks posts but it seems to be cut off from most of the decarb topics quoting dunks method.

Per Dunks method I used 1 gallon of gas, 3 oz oil and 1 can of seafoam, ran the engine on and off in 10 minute intervals until the gallon was gone. Didn't seem to smoke too much, but a noticeable amount of carbon was thrown out but a lot less than I expected for a 1986 2 stroke motor.

Fast forward 3 months and 50 hours later, I opted for the spray can version of seafoam (NOT Deep creep, that it not Seafoam.. It is equivalent to WD40).

For a carbed 2 stroke motor, this method is preferred:

With the Spray can version of seafoam, I sprayed the carb continuously for 1/2 of the can while keeping just enough throttle to keep it running, then let it die. Let that mix set for 15 minutes. Fire motor back up, and allow it to idle until that mix clears out, don't sit there and rev the motor to 'clear' out the pale oil, let it do this naturally at a fast idle. Then finish the rest of the can with the same method as the first, load it up until the can is empty and shut it off. Another 15 minutes soak and you are ready to fire up again.

This spray method resulted in tons of carbon exiting my engine and a much better running engine.

 

[Grub54891]

Never tried dunks method myself. His method states to do this every 50-60 hours, I suppose not as much carbon builds up in that time. I have done it your way,and it does work, most boaters don't do it and it results in more buildup. Once a season for me. Dunks method goes through the entire system. I run seafoam through every fall with the last can of fuel and have had no issues.

 

[jerryjerry05]

Decarb.
Mercury sells Power Tune
​OMC sells Engine Tuner.
Yam sells their equivalent.
These are all the same product.

I've never liked Seafoam.
I tried it in a test with the Mercury's product.
Sprayed some of each product in 2 jars.
Put a badly carbon'd piston in each jar.
Let it set overnight.
The Seafoam did nothing.
The Mercury had the stuff flaking off in huge chunks.
Seafoam might be good for something but I haven't figured out what??

 

[jwall116]

In the defense of Seafoam, you were letting it sit without any heat applied. I have not done any such of a test and am likely to give power tune a try the next round.

Does it smoke like seafoam? We all know that is pale oil and not carbon that is smoking.

 

[oldboat1]

At one of the auto repair forums, there was a DIY recommendation to mist the carb throat with the engine running to purge carbon (subject was an S-10 pickup with some running issues). I haven't tried that with cars, lawnmowers, outboards, or anything else -- but sounds like a shadetree method (or myth) that might go back a ways. I gather that the technique is a very light mist drawn in by the vacuum -- remember the poster talked about his vehicle exhaust "puking out" all kinds of nasties with his treatment. Anybody heard of this? (No need to flame me -- not recommending anything.... Just curious.)

 

[Grub54891]

Yeah back in the day.....We used to pour water down the carb slowly, so it would not hydrolock, then shut it down and let it soak a bit. re-start and blow out lots of carbon. Steam cleaning it was called. seemed to work ok back then. Nowadays everyone uses store bought treatments. Never did it to a 2-stroke though.

 

[tommarvin]

Do you get any carbon build up if you use 100% synthetic two stroke? I'm asking.

I watched a you-tube video test with seafoam, the before and after video looked the same, Next time were going with jerryjerry05 test results of Mercury's " power tune" he saw it work, with his own two eyes

 

[oldboat1]

Thanks, Grub. Good reminder.

 

[jwall116]

Carbon can not form with a true fully synthetic oil, however additives and impurities can cause burnt substances on internal parts. My Force outboard does not have a filter on the carb for one, not sure what year if any they began to install one.

I have 2 stroke engines for my model aircraft, running on redline racing oil that look brand new after 300+ hours. Shinny piston, great compression. This oil costs $12 per 16 oz bottle and 1 bottle makes 6 gallons of gas, that would get expensive. << NOT starting an oil brand war here. This is on an air cooled 2 stroke engine running on race gas.


Personally I would not introduce moisture to a 2 stroke engine running on a gas with alcohol in it. Our ethanol fuel is problematic enough without forcing water inside the engine. I will try that Power Tune cleaner next round.

Great discussion guys!

 

[Jiggz]

The use of water mist to decarb is still acceptable on 4 stroke engines but not quite on 2 stroke engines. The difference is the lubrication requirement of the stroke depends entirely on the fuel oil mix unlike the dedicated lube system of the 4 stroke engine.

 

[Frank Acampora]

In the good old days (1960s) when Detroit was experimenting with supercharging and turbocharging, a number of cars, notably Buick, were equipped with water injection to cool the mix when the charger kicked in. Some also used alcohol injection. Use of water for various purposes in an internal combustion engine is no new thing.

 

[oldboat1]

^^Grubb's note got me thinking back to the '60s when my dad talked about a water treatment back in the day (HIS day). I had other things to do in the '60s, I guess, so didn't pay much attention. Dad drove Buicks for years, though, so maybe he was into something.

An interesting old discussion here, just at random: http://www.thirdgen.org/forums/tech-general-engine/25876-does-misting-water-into.html (References to water injection and supercharging -- and aircraft engines.)

A leaking head gasket is excessive, I'm sure, but the job it does on carbon buildup is pretty impressive.

 

[ondarvr]

The use of water mist to decarb is still acceptable on 4 stroke engines but not quite on 2 stroke engines. The difference is the lubrication requirement of the stroke depends entirely on the fuel oil mix unlike the dedicated lube system of the 4 stroke engine.

The reason you don't want to do it on a 2 stroke is because the air and fuel go through the crankcase, so the water would be sucked through the crank, rod and wrist pin bearings, not a good idea if you want the motor to run very long.

 

[Frank Acampora]

Interesting discussion, oldboat but filled with half truths and misinformation in addition to some nuggets of good info. And pertaining to that discussion: Did you ever notice how well the old engines ran in a rainstorm? Not only is the air denser and cooler but it has 100% humidity. Does anyone think the air is dried before it enters the engine?

To quote Chuck Berry from "Maybelline": The rainwater splashing all under my hood, I knew it was doing my motor good. ----- The motor cooled down, the heat went down, and that's when I heard that highway sound. Cadillac sitting like a ton of lead. A hundred and ten a half a mile ahead. Maybelline, why can't you be true? Oh, Maybelline why cant you be true? You done started back doing the things you used to do. Oops, got carried away.

Misting water into a 2 cycle engine will not do ANY harm given the following conditions exist: 1. The engine is fully warmed up and 2. Afterward the engine is run long enough to evaporate any residual water.

I have dunked my 50 HP engine several times, filling it with water. Once back on shore I remove the plugs and crank the engine to blow out water. Then I put back the plugs and crank until the engine starts.After finally starting I run it for at least 1/2 hour to evaporate any water in the crankcase and under the flywheel. Bearings and all other surfaces still look brand new and engine runs very well.

 

[oldboat1]

Indeed! while motivatin' over the hill

[ed. and my nine point nine is still sublime, even after a watery ride.
...past Spring. OK so far, anyway.]

 

[ondarvr]

The lubrication properties of the oil are reduced when it's mixed with water, so depending on the amount added it may not harm anything, or it could create problems rather soon. 100% humidity is fine, in the hot motor the relative humidity will be even lower. I've dunked two strokes and sucked water into the motor many times when I raced motorcycles, short term exposure as the motor is dying is different than running under high stress to get more power out of it, then reducing the oils ability to do its job.

 

[oldboat1]

Yeah, dunking is a different matter (with some related issues).

Think in the decarbing context, "misting" would involve an idling motor (fast idle), fully warmed up. That's a ways afield from racing engines or WWII fighters trying to outrun Messerschmidts (or even Cadillacs racing Ford V8s in the rain.) It's not water injection. The old time steam cleaning method was not injection either. (I think carb cleaning would have been as far as it went with my Dad.)

I think proponents of misting to decarb (if there are any proponents) might argue that water is atomized when it enters from the carburetor, and vaporized at ignition. In a 2-cycle, that should mean there is no water on the downstroke -- only chance for water damage would be in the atomized fuel at intake. That is to say, chance for damage from occasional and intermittent misting is low. IMO, chance for damage would be weighed against use of harsh solvents to decarb -- in addition to comparing efficiencies of the two methods.

Now, I haven't done this. But the more I mull it over, I'm tempted to try it

 

[jerryjerry05]

jwall116. You mention "heat" when using Seafoam.
​Why would you need to heat it?
I'd be afraid of combustion???

The Power Tune works without any heat.
They say to run the motor to operating temp when using.
That enough heat to activate the SF?

Frank, I've seen the water injected into a running motor but like someone mentioned a 2 stroke "NOT" .
I've flushed a few dunkers and the way you did it is the best way.
I spray WD in the carbs/ intake to help remove the water.
It is WD-40(water displacement #40) or the 40th formula.

 

[Frank Acampora]

I was just using extreme examples to show that "misting" will do no harm in a 2 cycle engine.

Personally, I am not a proponent of ANY type of decarbonizing unless used as a "Hail Mary" procedure prior to or in hopes of avoiding a rebuild. Using modern oils, rings simply do not get carboned and stick in their grooves and a light coating of carbon on the piston crown will do no harm or cause poor running. I consider regular decarbon treatments to be useless and a make-work procedure just like regularly removing, cleaning, and repacking trailer bearings! It just makes the owner feel good that he/she is doing something. Let's see what kind of controversy that starts LOL.

Let's see: The last time I decarbonized an engine was-----never

 

[oldboat1]

^^^think that's well-stated, so will be a kiss a** and say so. Some kind of decarbing is step one or two in a lot of instructions here. I think cleaning the carb, fresh fuel, then just running the engine is pretty much the key. My old diesel cars are supposed to have Italian tune-ups now and then, and that might be appropriate for some outboards too, now and then (maybe running balls to the wall on the way back after a day of trolling.) But some prepping and just letting it run is the trick IMO. In any case, I don't see decarbing as routine maintenance.

But go after Frank, not me. He's the one who said it. I just embellished it some.