Decarbonizing Outboard

[PropsterII]

How do most of you feel about decarbonizing your outboard? Not talking about adding some Quick Clean or Ring Free to the fuel, unless you say that is sufficient if done on a regular basis, I'm referring more to the shock type treatment. If you recommend it, how often, what's the process, and what product do you use? I have a '95 Merc 150 hp EFI, so any process where you spray something in the carbs would not apply. I'd also be interested to know if there are any cons to doing this. I've heard anything from every 50-75 hrs to once a year near end of year. Also one treatment I've heard more than once is a full can of Seafoam in one gallon of gas in a separate tank, running this through a few times. I've only heard one or two say not to do it at all. Thanks in advance.

[delcecchi]

This a 2stroke efi or a 4stroke? If it is a two stroke, isn't there a throttle body, analogous to a carb, that the cleaner can be sprayed into?

And why do you think it needs decarbonization?

[Northlander]

Ring Free for me.

[jentz]

2 strokes I get the engine to running temp.Tilt the motor remove the plugs,Put 1/2

3/4 oz seafoam in the cylinders,reinstall the plugs let it sit 15 minutes,start it up and watch it smoke.Then take it out and run it to blow out carbon that was removed.

[PropsterII]

This is a 2 stroke EFI. It's running great right now but I'm reading and hearing more that it should be done on all engines, even 4 strokes carbon up apparently.

Jentz, a couple questions:

1. How often do you perform the procedure you describe?

2. After letting the Seafoam sit in the cylinders for 15 min and I start it up, do I let it idle in neutral or putt around at low speed before opening it up?

3. How long do you idle it before opening it up?

4. Do you change the plugs after or will they be "cleaned" as well in the process?

Thanks!

[delcecchi]

Mercury recommends "Remove engine deposits with Mercury Precision or Quicksilver

Power Tune Engine Cleaner." annually or every 100 hours.

[h8go4s]

Mercury recommends "Remove engine deposits with Mercury Precision or Quicksilver

Power Tune Engine Cleaner." annually or every 100 hours.

Interesting. I've been lurking on this forum and a couple of other fishing forums for 5 years, and this is the first time I've seen this topic come up. And I've owned 4 outboards over the last 40 years without even thinking about decarbing one. I'm wondering why a 4-stroke outboard would be different from a 4-stroke auto engine. If my car averaged 40 mph, 100 hours would be 4000 miles. Nobody decarbs an auto engine at 4000 mile intervals. Of course, rpm's on an auto engine are typically under 2000 at most speeds, so that needs to be considered, but wouldn't the higher rpm's typical in outboards mean less carbon deposits? It seems like Merc's recommendation is overkill by a lot.

[marine_man]

I've de-carbed 2 stroke, non EFI / DFI and seen a noticeable improvement in compression; I have not heard of doing this much on non-injected or 4 stroke motors in the past.

marine_man

[tacklejunkie]

I troll with an outboard on Superior. The rest I use my trolling motor. I used ring free in my other motors but I bought a boat that has an oil injection system. Would I still need to use ring free in that?

I only use non oxy gas in my boats if that matters

[delcecchi]

Mercury recommends "Remove engine deposits with Mercury Precision or Quicksilver

Power Tune Engine Cleaner." annually or every 100 hours.

[mallardnwalleye]

I have done it to old 2 strokes as jentz says. Works great. As others have said I wouldn't do it on efi motors as they shouldn't be dirty. I would clean the injectors on those. I would give it a shot on simple carbureted 4 strokes that have been idled down (trolled a lot).

Good luck!

[PropsterII]

This from another source regarding 4 strokes. Hard to know what to believe, so much is just anecdotal evidence.

"Four strokers are still prone to carbon buildup just not so much as two strokers which have oil in the combustion mixture. Four strokers suffer from the tendency for carbon buildup on the back (manifold side) of the intake valves. Carbon "pollops" (like little sponges) develop there and interfere with intake flow causing hesitation and loss of power."

[marine_man]

The earlier comment about ring free is a good one... it's a somewhat expensive additive, but it has shown to make a difference over time

marine_man

[Shorelunch]

The earlier comment about ring free is a good one... it's a somewhat expensive additive, but it has shown to make a difference over time

marine_man

Is Ring Free ok to use in non-Yammy 4strokes such as a Honda 225?

[marine_man]

Yes.. I'm not aware of any restrictions... I use it in all my 2 strokes

marine_man