Positive results from Seafoam and Dunk's decarb method

[UBETRUN]

I've been having some trouble with my port motor, at least one and maybe 2 cylinders have been dropping out. It wouldn't reach max rpm and you could smell gasoline at slow speeds. I changed the plugs and found one with a hunk of carbon across the electrodes. Thought new plugs would fix the problem but it didn't, the port motor still would occasionally foul a cylinder and drop rpm.

Yesterday, I used Dunk's decarb method with Seafoam. I warmed up the engines on the muffs to operating temp, dumped the gas and filled the fuel filters with Seafoam, ran the motors for a couple of minutes, let them sit for 10 minutes, ran them again for a few minutes (some smoke, some misfiring, neither excessive), dumped the gas and filled the fuel filters with Seafoam again, and then put the boat in the water. After idling out of the no wake zone, I hammered them for an hour straight up and down the Potomac. Not a single miss or instance when they wouldn't pull max rpm, both motors ran like a top from idle to just kissing the rev limiters. With only a couple hundred hours on the motors, I was surprised that I was having a carbon problem but with most of those hours trolling and not using any fuel additives, I guess it's the nature of the beast.

I've been procrastinating about using Dunk's method because I wasn't sure how the motors would react to straight Seafoam from the fuel filter. Now that I've done it, I can report that there is nothing to worry about, it works and is very easy to do. Many thanks to THT, $12 in Seafoam and an afternoon on the water is a lot better than taking it to the dealer.

[BW23]

Sounds good !

What brand of 2 stroke oil do you use and were you using any fuel additives prior to the decarb ?

[UBETRUN]

Always Mercury Premium or Premium Plus oil but no fuel additives. I am going to use Startron in the fuel from now on though as a little preventive medicine between yearly Seafoam treatments.

[waynesworld]

It worked for me on my f-225's as well.

[Capt. Fred]

Man that's very cool. It's not often that we can say 12 bucks fixed something on a boat!

[Mud Runner]

Congrats,

I've had similar results on the engines at work using Startron the same way.

[Brad1]

Rather than using the Startron to prevent carbon build up, why not just use Seafoam at the maintenance (preventative) level to prevent carbon build up?

Afterall, it's just proven to you how well it works using the more extreme Dunk's method.

Just a thought.

[Kajun]

add a can of seafoam to each tank of gas...

[handrelease]

can I do the same thing with ringfree, ie dump it in the secondary fuel filter (racor?). My f225 abruptly lost 400 rpms a few months ago. I have been buying gas from a cheap place that someone said uses a lower quality fuel. A friend of mine who buys gas at the same spot just lost 400 rpms off his top end too. thanks

[lt.willy]

Use the Sea Foam all year, every tank full and likely you will never have to do a major blow out again. I have heard the Startron is a good product, especially there fuel conditioner for closing up your boat for the winter, in the tank.
But I know from first and second hand experience there is nothing like Sea Foam for engine longevity, it works and a few very good friends who are marine mechanics tell me it is all they have used for many years.
They also tell me that the difference in the engine between one that has used it and one who has not is phenominal. Just my 2c's

[pappastratos]

I have never used the seafoam, I have read on the bassboatcentral.com where guys have decarboned using seafoam & have problems with their motors right after treatment. I like the idea of adding it to gas as a preventive,,

[carbo]

You can do the same thing with Mercury Engine Tuner. Eats fuel varnish better than carb cleaners.

[BW23]

I'm a firm believer it's better to use fuel additives with every fill up than the shock treatment !.

OEM oil and Ring free are OK by me !

[Bulls I]

I've done this on my Expedition through a vacuum port in the throttle body. Worked great. I can actually tell a difference.

[solarfry]

You can do same thing with StaBil..

[solarfry]

You can do same thing with ValveTec & StaBil..

Dreaded Flood Control is on. Sorry if it double or triple posts.

[UBETRUN]

Brad1 - 10/2/2007 7:47 AM

Rather than using the Startron to prevent carbon build up, why not just use Seafoam at the maintenance (preventative) level to prevent carbon build up?

The cost of Seafoam at the maintenance level is quite a bit more than Startron. My fuel tank is 218 gallons, that's roughly one 16 oz bottle of Startron compared to a gallon of Seafoam per fillup.

[rotorwrench]

That sounds like too concentrated of a treatment. http://www.thehulltruth.com/forums/thread-view.asp?tid=20628&posts=5&highlight=dunk's%20deca rb&highlightmode=1#M243962

[Mandopickr]

I first used Seafoam on my father's 60hp JOhnson, with great results. Then I decided to try Seafoam in my crankcase and in my gas in my Durango with 200,000 miles. I used a can to about 15 gals of gas, ran it for a few days, then topped off the tank with more gas. There was a noticeable improvement in the way it is running. However a couple of days ago I'm in a drivethru, and I look in my rearview at the cars behind me. They were almost impossible to see because of the smoke. I first I thought the motor was about to go, but I guess it was some of the residual seafoam. It stopped smoking a few miles later. I pity those people in the cars behind me.

[angjackson29]

I used dunk method on 115 Yamaha 4 stroke (3 times) that has lost top end speed and sounds bogged down when running a high rpms. Didn't get any smoke or carbon out of motor. It did pick up some while running on mixture, but still runs the same. Any ideas what the problem could be?